[hnemati]

Dear all
I am going to estimate the mach number in a pipe for Re=10000.
I know the speed of sound but I dont know how to calculate the Velocity of fluid to calculate the Ma number.
As all of you know, Re=(U*D/nu) where I know the real number of nu. As you see U*D is a constant =Re*nu. If I select D a big number then U is a small number therefore my Ma number is small but if I select D very small number U is big and then Ma is big.
Could someone help me whether is there any restriction of accounting D or not?
Bests

[FMDenaro]

Originally Posted by hnemati

Dear all
I am going to estimate the mach number in a pipe for Re=10000.
I know the speed of sound but I dont know how to calculate the Velocity of fluid to calculate the Ma number.
As all of you know, Re=(U*D/nu) where I know the real number of nu. As you see U*D is a constant =Re*nu. If I select D a big number then U is a small number therefore my Ma number is small but if I select D very small number U is big and then Ma is big.
Could someone help me whether is there any restriction of accounting D or not?
Bests

if D is too small, you could lie in the field of microfluidic where further effects in the flow can be relevant