Pressure loss calculation using CFD

February 4, 2004, 20:21

I would like to know whether we can calculate the pressure loss correctly using CFD such as Simple method.

Regards,

February 6, 2004, 00:35

As far as I know "Correctly" is a subjective word in CFD, It depends on the precision you want. If you accept the tolerance normally accepted for engineering problems, the answer could be yes. That is because CFD is never 100% accurate.

February 6, 2004, 19:38

Thank you for your suggestion.

My question is very simple.

If we consider the the flow in the straight pipe. If we must consider the continuty equation. Output flow speed should be equal with Input flow speed So, there is no energy loss. The pressure become is zero. This is my simple question.

Regards,

February 7, 2004, 12:46

Well, the total mass coming out is equal to the total mass going in, but the velocity profile at the outlet will be the same as the inlet profile only if you have defined the fully-developed profile as your inlet profile.

If you have no-slip boundaries, then there will be pressure variation. You can actually solve for the fully-developed velocity profile analytically. This will also give you the pressure variation.

-- Jarmo

February 4, 2004, 20:21	Pressure loss calculation using CFD	#1
Yoshi Guest Posts: n/a	I would like to know whether we can calculate the pressure loss correctly using CFD such as Simple method. Regards,

February 6, 2004, 00:35	Re: Pressure loss calculation using CFD	#2
CFD Learner Guest Posts: n/a	As far as I know "Correctly" is a subjective word in CFD, It depends on the precision you want. If you accept the tolerance normally accepted for engineering problems, the answer could be yes. That is because CFD is never 100% accurate.

February 6, 2004, 19:38	Re: Pressure loss calculation using CFD	#3
Yoshi Guest Posts: n/a	Thank you for your suggestion. My question is very simple. If we consider the the flow in the straight pipe. If we must consider the continuty equation. Output flow speed should be equal with Input flow speed So, there is no energy loss. The pressure become is zero. This is my simple question. Regards,

February 7, 2004, 12:46	Re: Pressure loss calculation using CFD	#4
Jarmo Monttinen Guest Posts: n/a	Well, the total mass coming out is equal to the total mass going in, but the velocity profile at the outlet will be the same as the inlet profile only if you have defined the fully-developed profile as your inlet profile. If you have no-slip boundaries, then there will be pressure variation. You can actually solve for the fully-developed velocity profile analytically. This will also give you the pressure variation. -- Jarmo

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