Over to you now Mohammad Amir

[Saj]

Well he's had catches dropped in England and in UAE and he's been unlucky at times.

The surfaces he's largely bowled on have been very flat, but having said that I don't think he's been at his best with the ball. We have only seen flashes of brilliance from him and at times he has looked ineffective with the ball and a bit laboured.

However to his credit he has continued to run in hard and give 100% and to expect miracles straight after his comeback was a bit much to ask.

However now we move onto New Zealand and Australia where the surfaces should be more to his liking and he should get more of a response from the pitches.

So Amir, over to you now, you have now got used to international cricket again and the pitches should be to your liking, so no room for excuses now.

 

[The_KING]

New Zealand pitches are green mambas on the first day and then flat for the rest of the match. I hope we win the toss and bowl first in NZ. Then we will really see what Amir is made of.

 

[Chief Destroyer]

New Zealand pitches are green mambas on the first day and then flat for the rest of the match. I hope we win the toss and bowl first in NZ. Then we will really see what Amir is made of.

The pitch only flattens if the sun is out for long periods. How the pitches behave will depend on the weather.

 

[Suleiman]

We'll have excuses for him in Aus and NZ as well rest assured if anything doesn't go according to plan.

Best of luck to him though. Really need a pacer who can make something happen rather than rely on Yasir for everything.

 

[Chief Destroyer]

We'll have excuses for him in Aus and NZ as well rest assured if anything doesn't go according to plan.

Best of luck to him though. Really need a pacer who can make something happen rather than rely on Yasir for everything.

We need a right arm pacer to support Amir and Wahab. Ali Imran Pasha would be the ideal choice.

 

[MenInG]

Well he's had catches dropped in England and in UAE and he's been unlucky at times.

The surfaces he's largely bowled on have been very flat, but having said that I don't think he's been at his best with the ball. We have only seen flashes of brilliance from him and at times he has looked ineffective with the ball and a bit laboured.

However to his credit he has continued to run in hard and give 100% and to expect miracles straight after his comeback was a bit much to ask.

However now we move onto New Zealand and Australia where the surfaces should be more to his liking and he should get more of a response from the pitches.

So Amir, over to you now, you have now got used to international cricket again and the pitches should be to your liking, so no room for excuses now.

I am surprised that all TV experts we have listened to have spoken highly of Amir; apart from a few on this forum, he seems to be doing well although the wickets column is a little weak.

New Zealand tour will be a test for him and he should come out with a bunch of wickets. if he fails there then serious questions will be asked for his future "automatic" inclusion in the Test side atleast.

 

[GLORY OF '92]

The golden boy will continue playing regardless. Outperformed by poor Rahat. Lack of questioning of his selection is bizarre.

 

[AlphaFighter]

The golden boy will continue playing regardless. Outperformed by poor Rahat. Lack of questioning of his selection is bizarre.

He is living of the 2010 England tour.

 

[GudduBadmash]

Dropped catches off his bowling otherwise he would have taken all 11 wickets leaving no man on the pitch

 

[shaz619]

I am surprised that all TV experts we have listened to have spoken highly of Amir; apart from a few on this forum, he seems to be doing well although the wickets column is a little weak.

New Zealand tour will be a test for him and he should come out with a bunch of wickets. if he fails there then serious questions will be asked for his future "automatic" inclusion in the Test side atleast.

If questions are going to be asked, may I ask what will the answers be? what resources do we have which could possibly do better then Amir?

 

[Mamoon]

He will get thrashed in Australia, might do well in New Zealand.

 

[hafizexpress]

We'll have excuses for him in Aus and NZ as well rest assured if anything doesn't go according to plan.

Best of luck to him though. Really need a pacer who can make something happen rather than rely on Yasir for everything.

Especially since Australia is anything but ideal for spinners, Yasir will probably not be the most effective. Amir will have to step up big time and take wickets rather than just conserving runs.

 

[GrandMaster]

Over to him now, but wait....same bunch of jokers will be fielding and yet again they will be dropping catches off his bowling?

 

[90MPH]

If he doesn't perform he shouldn't be selected, simple as that.

However I don't think it's excuses when so many easy catches are being dropped. Yeah sure occasionally it can happen but so many so often is unacceptable and for whatever reason he has suffered the most.

If anything the first priority for the NZ and Aus tours should be the catching and specifically slip catching because Pakistan can not afford to keep dropping catches whoever the bowler is.

As for Amir I think his performance has been satisfactory without being outstanding.

I personally think he's lacking some patience in his bowling - just needs to keep it tighter and not always search for wickets. He's got nearly everything a good fast bowler has but shouldn't get frustrated so easily.

 

[Hamza78]

If they don't hold his catches then it's not his fault

 

[msb314]

Amir has been decent so far - has not set the world on fire but has not been bad either.

Still an upgrade over Rahat, Sohail, Irfan etc.

Offers a good line and length at good pace too - hopefully will take more wickets when conditions suit him better.

 

[Ahson8]

We need a right arm pacer to support Amir and Wahab. Ali Imran Pasha would be the ideal choice.

I think Rahat'll do well in NZ.

I'd play Amir, Sohail, Rahat in NZ. Wahab'll come in for Rahat on the bouncier Australian tracks.

 

[Chief Destroyer]

I think Rahat'll do well in NZ.

I'd play Amir, Sohail, Rahat in NZ. Wahab'll come in for Rahat on the bouncier Australian tracks.

Can't drop Wahab. He's our game changer.

Mickey really should have gotten another right handed 5th seamer if he's not gonna bowl Imran. Just wasting a spot.

 

[waleed88]

Man I feel sad for Rahat... what has Rahat done to deserve such treatment, the guy plays one test match, looks an impressive bowler in both innings, and then gets dropped for Wahab Riaz to bowl with the new ball

 

[Hadi Rizvi]

If he doesn't perform he shouldn't be selected, simple as that.

However I don't think it's excuses when so many easy catches are being dropped. Yeah sure occasionally it can happen but so many so often is unacceptable and for whatever reason he has suffered the most.

If anything the first priority for the NZ and Aus tours should be the catching and specifically slip catching because Pakistan can not afford to keep dropping catches whoever the bowler is.

As for Amir I think his performance has been satisfactory without being outstanding.

I personally think he's lacking some patience in his bowling - just needs to keep it tighter and not always search for wickets. He's got nearly everything a good fast bowler has but shouldn't get frustrated so easily.

During the NZ tour he didn't get frustrated much even though the easiest of dollies were dropped. It was on the England tour that these dropped dollies got to his nerves. And then in the UAE in a crunch 150 chase he produced 2 chances in the 1st 2 overs and both dropped and it was then that he literally kicked the turf.

A fast bowler can only keep his cool for too long. Hopefully he starts looking for more LBW and bowled options rather than relying on the fielders or maybe he already is because that's why we feel that he is changing his line and length too early. Maybe he needs to trust the fielders more so that he can maintain a tight line and length.

He will come good in NZ and Aus inshallah.

 

[goran]

People demanding to drop Amir need to come up with better reasoning. He is still better than most of the crap pacers we have. I wouldn't mind dropping him if we had Wasims and Waqars waiting in the wings. But the fact is that our pacers are rubbish and Amir is the only bowler who is doing decent if not spectacular. He needs to be persisted with. We have seen enough trundlers in his absence, can't go back to 130 kph bowlers who are useless on any track in the world.

 

[a_jawad]

Im all for Amir and a fan of his, bit its sad when you consider the amount of leeway he gets because of those spells in UK and compare it to the treatment by us towards bowlers like Imran Khan and Junaid Khan who have practically spent their whole careers in UAE, run hard every game and not performed badly at all

 

[Ashraful_Rox]

He's still the best bowler from Pakistan. I think it will take him a couple of years, then he'll be deadly like Mitchell Starc. Kiwis will struggle big time against him, I think Warner will be his new bunny.

 

[Hasan123]

He's being put under too much pressure by Pakistan fans and media. Stop analysing all his deliveries and spells just let him bowl freely.

He's bowled okay in patches and average in other spells. He's going to start in NZ and down under. Needs to step up as pcb have invested a lot of time in him.

 

[street cricketer]

Will enjoy the conditions in New Zealand.

 

[Amjid Javed]

Hes lacking a break through bowling return in terms of loads of wickets since his return, but that will come. I can see him taking a 5 for soon in the kiwi and Aussie series and once his 100% confidence returns he will show what a quality bowler he is once again.

 

[shaz619]

Will enjoy the conditions in New Zealand.

What you're trying to say is that he's the Pakistani Bowling Version of Virat Kohli

 

[JibranAnsari]

In nz he might do well , in australia he will be taken to cleaners. Expect him take about 20 wickets in the next 5 matches @40 plus apiece.

 

[MenInG]

Seeing what Australia are upto, I am sure Amir will get a few wickets also.

 

[street cricketer]

What you're trying to say is that he's the Pakistani Bowling Version of Virat Kohli

I wasn't trying to denigrate him, if that was what you thought I was implying.

Any bowler requires atleast some amount of conditions to aid him. Both England and UAE weren't conducive to swing bowling, you cannot swing (conventionally) when there is nothing in the air and the pitch to aid swing/seam bowling. But I expect the conditions in New Zealand to aid him and be more suitable for his kind of bowling. Won't be surprised if he wreaks havoc there provided he gets to bowl first up and not after the wicket has become a patta.

 

[BDwarriors]

He will perform badly,but who is better than him on bench?

 

[Chief Destroyer]

I wasn't trying to denigrate him, if that was what you thought I was implying.

Any bowler requires atleast some amount of conditions to aid him. Both England and UAE weren't conducive to swing bowling, you cannot swing (conventionally) when there is nothing in the air and the pitch to aid swing/seam bowling. But I expect the conditions in New Zealand to aid him and be more suitable for his kind of bowling. Won't be surprised if he wreaks havoc there provided he gets to bowl first up and not after the wicket has become a patta.

There was enough swing in England but by the time he had regained control over length(4th test), it was too late. Cook was holding his bat out like an amateur and was there for the taking had Amir been in test form. Watch the 4th test opening spell to see what I'm talking about.

 

[shaz619]

I wasn't trying to denigrate him, if that was what you thought I was implying.

Any bowler requires atleast some amount of conditions to aid him. Both England and UAE weren't conducive to swing bowling, you cannot swing (conventionally) when there is nothing in the air and the pitch to aid swing/seam bowling. But I expect the conditions in New Zealand to aid him and be more suitable for his kind of bowling. Won't be surprised if he wreaks havoc there provided he gets to bowl first up and not after the wicket has become a patta.

I know but was just saying

Yeah conventional swing is achieved much like how aircraft wing's generate lift and the lift force tends to increase with the density of air, it's rarely cold in the UAE or humid and during the English summer this year the weather was generally pretty decent even though there wasn't as much grass on the surfaces swing could have been achieved if the weather allowed it.

The rougher side of the ball is a low pressure region while the smoother side of the ball is a high pressure region, do you know why this is the case? do you know which side of the ball the air flow travels faster and why?

 

[AlphaFighter]

If excuses are being made for Amir that he needs conducive conditions for wickets then he is just not good enough. He needs to be treated on par with the likes of Rahat, Wahab, Imran Khan and co and even Junaid Khan who have toiled away for their country in these conditions, Wahab has bent his back clocking 88-92 mph plus without complaining while Amir continues to receive excuses, sympathy, molly coddling. He needs to be treated at par with the other pacers or they need to be given the same amount of pampering as the other players. Fair is fair. You cannot have double standards and one rule for one and another rule for someone else.

 

[street cricketer]

There was enough swing in England but by the time he had regained control over length(4th test), it was too late. Cook was holding his bat out like an amateur and was there for the taking had Amir been in test form. Watch the 4th test opening spell to see what I'm talking about.

I saw swing in the first 2 days of Edgbaston and 1st day of the Oval test. Other than that, I didn't see the ball moving around for significant periods of time.

Remember Woakes and Rahat getting movement in the series.

 

[Indiafan]

Seeing what Australia are upto, I am sure Amir will get a few wickets also.

I am sure they will prepare much flatter wickets for Pakistan

 

[street cricketer]

I know but was just saying

Yeah conventional swing is achieved much like how aircraft wing's generate lift and the lift force tends to increase with the density of air, it's rarely cold in the UAE or humid and during the English summer this year the weather was generally pretty decent even though there wasn't as much grass on the surfaces swing could have been achieved if the weather allowed it.

The rougher side of the ball is a low pressure region while the smoother side of the ball is a high pressure region, do you know why this is the case? do you know which side of the ball the air flow travels faster and why?

Lmao I don't know about the intricate physics of swing bowling mate.

I just know that the new ball moves towards the rougher side when it swings conventionally (with seam position alignment) and towards the shinier side when the old ball starts reversing (after the ball is maintained to the required condition for reverse swing).

 

[shaz619]

Lmao I don't know about the intricate physics of swing bowling mate.

I just know that the new ball moves towards the rougher side when it swings conventionally (with seam position alignment) and towards the shinier side when the old ball starts reversing (after the ball is maintained to the required condition for reverse swing).

I was trying to picture it in my head, I understand that with a cambered aerofoil the top region air flow travels quicker but the pressure is low while the bottom surface which isn't cambered air travels slower and the pressure is high, the pressure difference between the top and bottom surfaces causes the lift force. Both surfaces are smooth and while the principle is similar when it comes to cricket balls the distinct rough/shiny surfaces make the situation a bit unique.

I figured it out in the process of typing this post and looking at this picture:

You see the dot on the smoother surface of the cricket ball? that is something called the separation point; it is also visible on the rougher side but unlike on the smoother surface it is behind the cricket ball. When airflow hits the cricket ball something called a boundary layer develops on the surfaces and it separates from the ball at some point.

The separation point can also be seen as the period where laminar flow becomes turbulent, on a smoother surface you're going to get laminar flow mostly. On the rougher side however with the separation point at the back the flow becomes turbulent a little later.

What I didn't understand was why the speed of the airflow is quicker at the top of the cricket ball in the rough region because on first look you'd think it would slow down given the nature of the roughness but that's where I was wrong, you see on the bottom surface where the flow is laminar? the velocity of the air is lower because it doesn't cover as much distance as it does on the rough surface.

And the transition from a laminar to a turbulent state happens at the critical speed, the critical speed is dependent on the surface roughness. The rougher surface has the lower critical velocity; this makes sense because the air is travelling faster over this region given that more distance is being covered. On the smoother surface the critical velocity is higher because not as much distance is being covered given the nature of the surface the flow separates a lot earlier (this was the confusing part).

The separation point is really important because it will determine whether the pressure is low or high and the difference between the two pressures on the rough and smooth surface will generate the lift force or swing.

 

[Bhaag Viru Bhaag]

'Over to you now Mohammed Amir' - Pakistani fans, Captain Misbah and PCB

Amir's reply

'Over to you fielders' - Amir

 

[Chief Destroyer]

I saw swing in the first 2 days of Edgbaston and 1st day of the Oval test. Other than that, I didn't see the ball moving around for significant periods of time.

Remember Woakes and Rahat getting movement in the series.

Yeah, you're right. The only time it swung for long periods were the first two days of Edgbaston. But generally, there was new ball swing available for 20 overs or so, regardless of the dry weather.

 

[Saj]

He will perform badly,but who is better than him on bench?

Well he's not an automatic selection. At the end of the day it's wickets that matter. If he doesn't take wickets the selectors will move on, despite his good reputation.

 

[AlphaFighter]

Well he's not an automatic selection. At the end of the day it's wickets that matter. If he doesn't take wickets the selectors will move on, despite his good reputation.

There was no reputation to begin with. He was lucky to have played in excellent bowling conditions in England in 2010. His bowling averages in Sri lanka, New Zealand and Australia were nothing to write home about to begin with. If it hadnt been for the spot fixing ban, he would have proven to be another Junaid, Rahat, Wahab and might have struggled to maintain his place in the team.

 

[joly]

We'll have excuses for him in Aus and NZ as well rest assured if anything doesn't go according to plan.

Best of luck to him though. Really need a pacer who can make something happen rather than rely on Yasir for everything.

How come the best pacer in Asia need helpful pitches to take 3 wickets per match? What's so great then??

 

[Suleiman]

How come the best pacer in Asia need helpful pitches to take 3 wickets per match? What's so great then??

What? completely lost me there, didn't understand your question.

 

[Junaids]

Well he's had catches dropped in England and in UAE and he's been unlucky at times.

The surfaces he's largely bowled on have been very flat, but having said that I don't think he's been at his best with the ball. We have only seen flashes of brilliance from him and at times he has looked ineffective with the ball and a bit laboured.

However to his credit he has continued to run in hard and give 100% and to expect miracles straight after his comeback was a bit much to ask.

However now we move onto New Zealand and Australia where the surfaces should be more to his liking and he should get more of a response from the pitches.

So Amir, over to you now, you have now got used to international cricket again and the pitches should be to your liking, so no room for excuses now.

That's a bit ambitious. How can it be "over to" Amir?

Mohammad Amir is good, but how is he meant to take catches at slip off his own bowling?

 

[Indiafan]

That's a bit ambitious. How can it be "over to" Amir?

Mohammad Amir is good, but how is he meant to take catches at slip off his own bowling?

In England catches were dropped of other bowlers too yet they performed better than him. The truly good/great Pak bowlers of the past like Sohaib had lots of catches dropped of them yet did well. Wasn't this catches dropped one of the excuses for Sami supporters for a while? Is that the level of Amir now?

 

[big_gamer007]

It's your own fault, the way he was hyped over here was just stupid.. He did well in clouded conditions in England in 2010 and everyone thought he will always be performing the same way.. the fan expectation were too high, give him a year or two to settle down in the team and treat him like every other bowler and not like some Demi god..

 

[Shafi]

Australia test will be most likely last for Amir before gets dropped. In next 5 tests our fielders will drop atleast 10-15 catches if not more and let Amir gets only 10-12 wickets (Instead of 20+ wickets). 10 wickets in 5 matches will be good enough to drop him as our formers are already against his inclusion.

 

[Shafi]

In England catches were dropped of other bowlers too yet they performed better than him. The truly good/great Pak bowlers of the past like Sohaib had lots of catches dropped of them yet did well. Wasn't this catches dropped one of the excuses for Sami supporters for a while? Is that the level of Amir now?

Yeah but no body drops 12+ catches of a particular bowler in both side.

 

[Saj]

That's a bit ambitious. How can it be "over to" Amir?

Mohammad Amir is good, but how is he meant to take catches at slip off his own bowling?

Who has said it's just about dropped catches?

 

[Junaids]

Who has said it's just about dropped catches?

My point is that if 90% of slip chances were taken off him - which is the norm worldwide - then Amir would have topped the bowling averages in both series that he has played.

I'm not referring to you, but there is a tendency for Pakistan fans to expect him to be the new Wasim Akram, bowling searing yorkers to dismiss people LBW and bowled.

It's never going to happen. If you watch the 17 year old Wasim Akram at the World Championship of Cricket in Australia in 1985, you see in Wasim's 5 wicket haul v Australia that he was ALWAYS faster than Mohammad Amir.

But more than that, the new video-enforced exclusion zones for running on the wicket have ensured that Amir has to bowl much wider of the stumps than he did in 2010, and delivering from wider than Wasim Akram EVER bowled.

All in all it means that all the Pakistan left-arm quicks - Amir, Rahat, Wahab and Junaid if he returns are all going to have to bowl from wider of the crease, and will not be dismissing people LBW ever, and won't get too many bowleds either.

To his credit, Amir is instead adapting and becoming skilled at getting edges to the slip cordon.

But those edges have to be taken. And I have no great confidence in Pakistan's ageing slips to have the hand-eye coordination to snaffle those edges.

 

[Saj]

My point is that if 90% of slip chances were taken off him - which is the norm worldwide - then Amir would have topped the bowling averages in both series that he has played.

I'm not referring to you, but there is a tendency for Pakistan fans to expect him to be the new Wasim Akram, bowling searing yorkers to dismiss people LBW and bowled.

It's never going to happen. If you watch the 17 year old Wasim Akram at the World Championship of Cricket in Australia in 1985, you see in Wasim's 5 wicket haul v Australia that he was ALWAYS faster than Mohammad Amir.

But more than that, the new video-enforced exclusion zones for running on the wicket have ensured that Amir has to bowl much wider of the stumps than he did in 2010, and delivering from wider than Wasim Akram EVER bowled.

All in all it means that all the Pakistan left-arm quicks - Amir, Rahat, Wahab and Junaid if he returns are all going to have to bowl from wider of the crease, and will not be dismissing people LBW ever, and won't get too many bowleds either.

To his credit, Amir is instead adapting and becoming skilled at getting edges to the slip cordon.

But those edges have to be taken. And I have no great confidence in Pakistan's ageing slips to have the hand-eye coordination to snaffle those edges.

I agree that his figures would have looked a lot better if the catches or at least most of them had been taken, but my concern at the moment is that he has not consistently bowled well in Tests since his comeback. I reiterate that we have only seen him bowl well occasionally and not on a regular basis.

 

[Junaids]

I agree that his figures would have looked a lot better if the catches or at least most of them had been taken, but my concern at the moment is that he has not consistently bowled well in Tests since his comeback. I reiterate that we have only seen him bowl well occasionally and not on a regular basis.

Fair comments.

But Pakistan is going to have real problems with the interplay of two factors:

1. Misbah wanting 3 quicks plus 1 spinner outside Asia, and
2. The new enforcement of running-on-the-wicket zones.

This means that even playing two left-arm quicks is risky in a 4 man attack.

I think that at some point in the next few Tests we will see Pakistan have two left-arm quicks thrown out of the attack. And Amir will edge wider and wider and wider......

 

[The_Odd_One]

He just had a great ODI series in NZ, will do well in tests too.

The amount of criticism he gets is unbelievable. In England, both Anderson and Broad were toothless and the UAE pitches were dead too. People should lower their expectations. He makes it on the team on merit and I am sure if he doesn't perform well in the next two tours, he will be rightly dropped.

 

[Napa]

What you're trying to say is that he's the Pakistani Bowling Version of Virat Kohli

I am impressed by your ability to somehow bring Kohli into the discussion in this unrelated thread!

 

[Indiafan]

He just had a great ODI series in NZ, will do well in tests too.

The amount of criticism he gets is unbelievable. In England, both Anderson and Broad were toothless and the UAE pitches were dead too. People should lower their expectations. He makes it on the team on merit and I am sure if he doesn't perform well in the next two tours, he will be rightly dropped.

Anderson averaged 25, Broad 28 and Amir 42

 

[Indiafan]

Yeah but no body drops 12+ catches of a particular bowler in both side.

Sure. How many catches of Akhtar did Akmal drop? What's Akhtar's bowling average? And Amir was compared with Akram who is much better than even Akhtar

 

[Sports_Psychologist]

Well he's had catches dropped in England and in UAE and he's been unlucky at times.

The surfaces he's largely bowled on have been very flat, but having said that I don't think he's been at his best with the ball. We have only seen flashes of brilliance from him and at times he has looked ineffective with the ball and a bit laboured.

However to his credit he has continued to run in hard and give 100% and to expect miracles straight after his comeback was a bit much to ask.

However now we move onto New Zealand and Australia where the surfaces should be more to his liking and he should get more of a response from the pitches.

So Amir, over to you now, you have now got used to international cricket again and the pitches should be to your liking, so no room for excuses now.

Just double his wickets that he has taken because of the pathetic fielding by our team,

 

[Napa]

I was trying to picture it in my head, I understand that with a cambered aerofoil the top region air flow travels quicker but the pressure is low while the bottom surface which isn't cambered air travels slower and the pressure is high, the pressure difference between the top and bottom surfaces causes the lift force. Both surfaces are smooth and while the principle is similar when it comes to cricket balls the distinct rough/shiny surfaces make the situation a bit unique.

I figured it out in the process of typing this post and looking at this picture:

You see the dot on the smoother surface of the cricket ball? that is something called the separation point; it is also visible on the rougher side but unlike on the smoother surface it is behind the cricket ball. When airflow hits the cricket ball something called a boundary layer develops on the surfaces and it separates from the ball at some point.

<b>1. The separation point can also be seen as the period where laminar flow becomes turbulent, on a smoother surface you're going to get laminar flow mostly.</b> On the rougher side however with the separation point at the back the flow becomes turbulent a little later.

What I didn't understand was why the speed of the airflow is quicker at the top of the cricket ball in the rough region because on first look you'd think it would slow down given the nature of the roughness but that's where I was wrong, you see on the bottom surface where the flow is laminar? the velocity of the air is lower because it doesn't cover as much distance as it does on the rough surface.

And the transition from a laminar to a turbulent state happens at the critical speed, the critical speed is dependent on the surface roughness. The rougher surface has the lower critical velocity; this makes sense because the air is travelling faster over this region given that more distance is being covered. <b>2. On the smoother surface the critical velocity is higher because not as much distance is being covered given the nature of the surface the flow separates a lot earlier (this was the confusing part). </b>

The separation point is really important because it will determine whether the pressure is low or high and the difference between the two pressures on the rough and smooth surface will generate the lift force or swing.

The mechanics of this is explained in:

http://www.espncricinfo.com/magazine/content/story/258645.html

I didn't do a course in fluid dynamics, but physics is a pleasure so I will give this a shot.

The important thing to understand here is that there is a layer of air that is traveling with the ball (a dynamic layer, some of it dissipates and is replenished). This "boundary layer" has a relative speed to the (relatively stagnant) air around it, so by Bernoulli's Principle it develops low pressure (the sum of the pressure, velocity and potential heads have to be constant, and the "boundary layer" has a larger velocity head, therefore a smaller pressure head).

1. No. The "separation point" is where the "boundary layer" of air "leaves" the ball's surface. As per Mehta, a turbulent "boundary layer" sticks to the ball's surface for more of the ball's surface (see picture) for "conventional swing". According to Mehta this happens with the turbulent air "because of its increased activity and energy"

A later "separation point" on the turbulent side means that the surface area of contact between the layer of "turbulent air" and the ball is greater (hence greater force). More surface of lower pressure would result in greater net force (area x pressure) and the net force on the ball should move it towards the turbulent side.

I read the article quickly (my patience is not what it used to be) so maybe I missed it, but Mehta doesn't seem to say that that the "turbulent layer" also has greater velocity (which seems possible given that the air will both be traveling with the ball and also randomly along the surface) which would create even lower pressure.

Mehta seems to say that the net force is generated due to the fact that the "boundary layer" of turbulent air is over a greater amount of the ball's surface compared to laminar air.

2. According to the Mehta article he seems to be say the chain of causality is:

rough surface -> turbulent air -> increased energy -> later point of separation

That air flowing over a rough surface should be turbulent is intuitive. Kind of like a river where you get white water over the rocks. Impediments to fluid flow will produce turbulence.

It is a bit disappointing to see a physicist use inaccurate terminology. Mehta writes "The location of this separation point determines the pressure, and a relatively late separation results in lower pressure on that side." He should use "force" instead of pressure. Force = Pressure x Area or the integral of pressure over area is pressure is not taken as constant.

 

[TalentSpotterPk]

Amir is still unable to ball a delivery with upright seam which goes with the angle against a right hand batsman.


This was his stock delivery from 2009-2010 while the inswinger was the surprise delivery after setting up the batsman. For Left handed batsman the case was opposite.


His wrist and fingers are not behind the ball when he wants to slant the ball across right handed batsman hence he bowls a semi cutter which is easily picked by the batsman. Because he cuts the seam hence he loses 5 - 7 kph speed aswell.


With this the batsman playing him aren't guessing while playing him like 2009-2010 as they can easily read what is presented to them.



In this series there was another issue. He wasn't able to impart the same number of opposite revolutions on his inswinger as we saw in somerset game and in Asia Cup so he got minimal swing on inswinger even in first few overs. Yes the atmosphere isn't conducive for swing bowling but still he should have got half the swing atleast for first 3-4 overs.




Now there are not match fitness related issues. These issues need technical assistance and fine tuning.



Amir needs help of somebody like Kabir Khan or Chaminda Vaas in nets to revive the Amir of 2009-2010. Only they can tell him the drills to sort out this issue. None of them is available and I don't see Wasim Akram working with Amir in NCA nets for 4-5 days.




Azhar Mehmood used to have good outswinger with the seam pointing towards 1st slip and even with his straighter delivery or the one which seamed back he used to present an upright seam. Let's see whether as a right arm pacer he can fix these 2 issues of Amir or not ? I hope he does.



I guarantee that if InshaAllah Amir sorts these two issues than it will be revival of 2009-2010 Amir who was a matchwinner and an absolute treat to watch.



Now its all about " IF "

 

[Deewana Mastana]

Apart from the T20's, I am yet to see him bowl over 140k's consistently. He has mostly hovered in the 132 and going to 140k occasionally and then one odd one over that.

His swing has not been there mostly so far since his comeback either but again it his release point that has caused that to happen and the angle.

Once he works out those glitches with a competent bowling coach who points these out to him, we may just see the start of a Mohammad Amir in NZ and Australia that we saw glimpses of in 2010.

 

[The_Odd_One]

Anderson averaged 25, Broad 28 and Amir 42

Bothered to check how many wickets they took? How many times did they destroy Pakistani batting?

 

[shaz619]

The mechanics of this is explained in:

http://www.espncricinfo.com/magazine/content/story/258645.html

I didn't do a course in fluid dynamics, but physics is a pleasure so I will give this a shot.

The important thing to understand here is that there is a layer of air that is traveling with the ball (a dynamic layer, some of it dissipates and is replenished). This "boundary layer" has a relative speed to the (relatively stagnant) air around it, so by Bernoulli's Principle it develops low pressure (the sum of the pressure, velocity and potential heads have to be constant, and the "boundary layer" has a larger velocity head, therefore a smaller pressure head).

1. No. The "separation point" is where the "boundary layer" of air "leaves" the ball's surface. As per Mehta, a turbulent "boundary layer" sticks to the ball's surface for more of the ball's surface (see picture) for "conventional swing". According to Mehta this happens with the turbulent air "because of its increased activity and energy"

A later "separation point" on the turbulent side means that the surface area of contact between the layer of "turbulent air" and the ball is greater (hence greater force). More surface of lower pressure would result in greater net force (area x pressure) and the net force on the ball should move it towards the turbulent side.

I read the article quickly (my patience is not what it used to be) so maybe I missed it, but Mehta doesn't seem to say that that the "turbulent layer" also has greater velocity (which seems possible given that the air will both be traveling with the ball and also randomly along the surface) which would create even lower pressure.

Mehta seems to say that the net force is generated due to the fact that the "boundary layer" of turbulent air is over a greater amount of the ball's surface compared to laminar air.

2. According to the Mehta article he seems to be say the chain of causality is:

rough surface -> turbulent air -> increased energy -> later point of separation

That air flowing over a rough surface should be turbulent is intuitive. Kind of like a river where you get white water over the rocks. Impediments to fluid flow will produce turbulence.

It is a bit disappointing to see a physicist use inaccurate terminology. Mehta writes "The location of this separation point determines the pressure, and a relatively late separation results in lower pressure on that side." He should use "force" instead of pressure. Force = Pressure x Area or the integral of pressure over area is pressure is not taken as constant.

No, the laminar flow does become turbulent because flow separation involves the laminar flow leaving the objects surface and forming eddies plus vortices which are major components of turbulent flow. A boundary layer is a layer of more or less stationary fluid immediately surrounding an immersed moving object, this is a behaviour which described the "Flow" I was referring to which becomes turbulent beyond the separation point but it's position is dependent on the nature of the object.

I understood everything else but couldn't get my head around the velocity on the rougher side but get it now but was struggling to explain to a friend why the flow is not entirely turbulent when it hits the rough surface. The separation point is vital when it comes to generating lift, it's one of the reasons why we have cambered aerofoils because it delays the flow becoming turbulent as this causes an increase in drag.

 

[anuk]

if aamir is performing close to 50% of his skill level, it's going to be a bloodbath. i cannot wait to watch guys like guptill and latham squirm and wriggle in their fruitless attempts to keep aamir's thunderbolts out. mashallah.

 

[AlphaFighter]

His performances have declined gradually since his comeback in January to April 2016, maybe it is a lack of fitness and the fact he is not used to playing cricket continuously on the trot and bowling long spells. He doesn't have a single man of the match award since his comeback.

 

[Shafi]

His performances have declined gradually since his comeback in January to April 2016, maybe it is a lack of fitness and the fact he is not used to playing cricket continuously on the trot and bowling long spells. He doesn't have a single man of the match award since his comeback.

So whom you think is the replacement of Amir??? Mir Hamza, Sadaf, Ehsan Adil or Zia-ul Haq????

 

[Napa]

No, the laminar flow does become turbulent because flow separation involves the laminar flow leaving the objects surface and forming eddies plus vortices which are major components of turbulent flow. A boundary layer is a layer of more or less stationary fluid immediately surrounding an immersed moving object, this is a behaviour which described the "Flow" I was referring to which becomes turbulent beyond the separation point but it's position is dependent on the nature of the object.

I understood everything else but couldn't get my head around the velocity on the rougher side but get it now but was struggling to explain to a friend why the flow is not entirely turbulent when it hits the rough surface. The separation point is vital when it comes to generating lift, it's one of the reasons why we have cambered aerofoils because it delays the flow becoming turbulent as this causes an increase in drag.

I assume you are basing your analysis on Rabindra Mehta's article as you use a picture from his article. I do not know why you said "No" to my post as it simply a summary of Mehta's article.

"No, the laminar flow does become turbulent because flow separation involves the laminar flow leaving the objects surface and forming eddies plus vortices which are major components of turbulent flow." This is a description of what turbulent flow is, rather than the reason why it happens. As Mehta says, whether the flow is laminar or turbulent depends upon the "critical speed", which is determined by the roughness of the surface.

A cambered aerofoil has a greater maximum lift coefficient because it is asymmetrical in shape. A cricket ball is symmetrical in shape. The asymmetry in a cricket ball is caused by unequal roughness rather than shape. That is why Mehta doesn't use the phrase "camber aerofoil" in his article.

 

[shaz619]

I assume you are basing your analysis on Rabindra Mehta's article as you use a picture from his article. I do not know why you said "No" to my post as it simply a summary of Mehta's article.

"No, the laminar flow does become turbulent because flow separation involves the laminar flow leaving the objects surface and forming eddies plus vortices which are major components of turbulent flow." This is a description of what turbulent flow is, rather than the reason why it happens. As Mehta says, whether the flow is laminar or turbulent depends upon the "critical speed", which is determined by the roughness of the surface.

A cambered aerofoil has a greater maximum lift coefficient because it is asymmetrical in shape. A cricket ball is symmetrical in shape. The asymmetry in a cricket ball is caused by unequal roughness rather than shape. That is why Mehta doesn't use the phrase "camber aerofoil" in his article.

I read his stuff but didn't go by his analysis entirely and he didn't mention the flow's velocity I think that's something which is important but couldn't get my head around it at first. I've studied fluid mechanics, CFD, low speed/high speed aerodynamics as well but obviously miya no expert . His analysis is excellent still. I said no to the part where you disagreed with the flow becoming turbulent beyond the separation point, Mehta didn't outlaw that it's just basic stuff. The cambered aerofoil was just an analogy used to explain the importance of a separation point when it comes to generating lift.

You took Physics at degree level?

 

[Napa]

I read his stuff but didn't go by his analysis entirely and he didn't mention the flow's velocity I think that's something which is important but couldn't get my head around it at first. I've studied fluid mechanics, CFD, low speed/high speed aerodynamics as well but obviously miya no expert . His analysis is excellent still. <b>I said no to the part where you disagreed with the flow becoming turbulent beyond the separation point,</b> Mehta didn't outlaw that it's just basic stuff. The cambered aerofoil was just an analogy used to explain the importance of a separation point when it comes to generating lift.

You took Physics at degree level?

I didn't say anything about what happens to the flow beyond the "separation point". It doesn't matter as beyond the "separation point" the flow is no longer in contact with the ball and therefore doesn't contribute to the net force on the ball.

I did multiple Physics courses (ranging from Mechanics to Quantum Mechanics) in my first two years at the World's Greatest Engineering College (which has multiple campuses in India)

 

[shaz619]

I didn't say anything about what happens to the flow beyond the "separation point". It doesn't matter as beyond the "separation point" the flow is no longer in contact with the ball and therefore doesn't contribute to the net force on the ball.

I did multiple Physics courses (ranging from Mechanics to Quantum Mechanics) in my first two years at the World's Greatest Engineering College (which has multiple campuses in India)

The position/timing of the separation point or when that flow becomes turbulent is really important and to "the flow is no longer in contact with the ball" I'd say yes and no to that because when it comes to the rough surface, you can see from the image eddies/vortices are present temporarily on the surface before separating unlike on the smooth side of the ball. Which college is that? I pay little attention to the world rankings, I've studied those subjects to before Uni they are incredibly challenging but really interesting to

 

[cricket_cfa]

i wish amir best and hope pak pacers take wickets with new ball. This will boost our team.
Will yasir shah be effective in NZL ?

 

[Napa]

The position/timing of the separation point or when that flow becomes turbulent is really important and to "the flow is no longer in contact with the ball" I'd say yes and no to that because when it comes to the rough surface, you can see from the image eddies/vortices are present temporarily on the surface before separating unlike on the smooth side of the ball. Which college is that? I pay little attention to the world rankings, I've studied those subjects to before Uni they are incredibly challenging but really interesting to

Same college that provides McKinsey with the highest percentage of consultants, that CEO of Google graduated from, and Nobel laureate Venkatraman Ramakrishnan couldn't get into.

 

[Saj]

Bowled too short so far in New Zealand.

Needs to pitch the ball up more than he was.

Swing not there either.

 

[Ami]

He'll be alright...its all gonna click soon.
Once he gets his first fifer he would have arrived.
Remember, he stopped learning, improving for 6 years...so its gonna take time to catch up.

 

[Buffet]

Bowled too short so far in New Zealand.

Needs to pitch the ball up more than he was.

Swing not there either.

Some Amir fans will find few examples of balls swinging due to pitching it up and prove you wrong.

--

Agree here. He should have allowed ball to swing. He bowled too short. Still, new day and new session coming so you never know. He may find his radar and for Pakistan's sake, quicker he does, better it will be. Pakistan needs to dismiss NZ quickly.

 

[srh]

not good enough; he is lucky that Pakistan is currently going through a drought of good fast bowlers otherwise he would not even make the squad

 

[KhanNn]

Doesn't make sense. He bowled well against Somerset....Maybe with time he will get better? Maybe Wasim Akram can help?

 

[Saj]

Bowled a slightly better length last night but still far from ideal.

 

[Amirforpresident]

I dont get it. He was swinging it against Somerset and a bit against WI in the last test match in 2nd innings I believe when misbah dropped his catch. Why cant he do it right now?
Is he afraid of getting to close to the stump?
He is Bowling way to wide of the crease to Swing it away from the left hander.

 

[Varun]

Greentop, and the wickets have come.

Knew it!