Simulating supersonic flow in a spinning nozzle

Syed Wajeeh · April 25, 2022, 07:39

Hello all.
I am new to ANSYS fluent and I am simulating internal compressible flow in a nozzle which is spinning*about its axis. I have run the simple simulations which work fine but when I give rotations to the wall or just to the whole solid body, the simulations get complete but I am unable to get the desired result as my streamlines and flow both are still straight. Can someone please help me to model and analyze this properly? I will be very thankful

WhatsApp Image 2022-04-25 at 3.09.46 PM.jpeg

agd · April 25, 2022, 12:04

Are you running inviscid? Or, if you are running viscous do you have the correct BC set at the solid wall - it won't be zero velocity for the flow.

Syed Wajeeh · April 25, 2022, 16:03

Hello agd. My BCs are inlet pressure = 5.099MPa, Outlet Pressure = 101325 Pa. Left and rights faces are Symmetry-1 and Symmetry-2 and wall is moving wall with rotational velocity of 62.83 rad/s, axis origin at the start of inlet and in the direction of X.
Please tell me if I am wrong at some step.
Or if there is any other method of applying spin to the nozzle.
Thanks in advance

Syed Wajeeh · April 25, 2022, 16:05

I am running k-w SST.

LuckyTran · April 25, 2022, 21:24

You should be using periodic boundary conditions and not symmetry conditions. Symmetry conditions will make the flow always straight.

With that being said, I have no clue how it even converged.

Syed Wajeeh · April 26, 2022, 04:52

Lucky can you help me in understanding why should I be using periodic conditions and how can I set up these in my problem in ANSYS fluent? I will be very thankful to you

LuckyTran · April 26, 2022, 10:16

Because the velocity normal to the symmetry plane must be 0 or it wouldn't be symmetry. That is, no flow vector can cross the symmetry plane. And that means that the flow will always be parallel to the plane.

Syed Wajeeh · April 26, 2022, 19:38

Got it. Thanks a ton Mate. Stay blessed

April 25, 2022, 07:39	Simulating supersonic flow in a spinning nozzle	#1
Syed Wajeeh Member Syed Wajeeh Join Date: Mar 2022 Posts: 56 Rep Power: 4	Hello all. I am new to ANSYS fluent and I am simulating internal compressible flow in a nozzle which is spinning*about its axis. I have run the simple simulations which work fine but when I give rotations to the wall or just to the whole solid body, the simulations get complete but I am unable to get the desired result as my streamlines and flow both are still straight. Can someone please help me to model and analyze this properly? I will be very thankful WhatsApp Image 2022-04-25 at 3.09.46 PM.jpeg

April 25, 2022, 12:04		#2
agd Senior Member Join Date: Jul 2009 Posts: 351 Rep Power: 18	Are you running inviscid? Or, if you are running viscous do you have the correct BC set at the solid wall - it won't be zero velocity for the flow. Syed Wajeeh likes this.

April 25, 2022, 21:24		#5
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	You should be using periodic boundary conditions and not symmetry conditions. Symmetry conditions will make the flow always straight. With that being said, I have no clue how it even converged. erkampasha, aero_head and Syed Wajeeh like this.

April 26, 2022, 10:16		#7
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	Because the velocity normal to the symmetry plane must be 0 or it wouldn't be symmetry. That is, no flow vector can cross the symmetry plane. And that means that the flow will always be parallel to the plane. Syed Wajeeh likes this.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Pressure Driven Supersonic Flow in Converging-Diverging Nozzle	cdm	OpenFOAM Running, Solving & CFD	7	August 28, 2019 01:37
how to simulate orifice in supersonic flow?	YING	FLUENT	2	May 16, 2013 10:41
reversed flow in over-expanded supersonic nozzle	imnull	FLUENT	0	March 28, 2013 10:48
Supersonic nozzle exit conditions	Betty	Main CFD Forum	13	May 24, 2012 00:26
compressible flow in a counterflow nozzle	d.vamsidhar	FLUENT	0	November 24, 2005 01:45

April 25, 2022, 16:03		#3
Syed Wajeeh Member Syed Wajeeh Join Date: Mar 2022 Posts: 56 Rep Power: 4	Hello agd. My BCs are inlet pressure = 5.099MPa, Outlet Pressure = 101325 Pa. Left and rights faces are Symmetry-1 and Symmetry-2 and wall is moving wall with rotational velocity of 62.83 rad/s, axis origin at the start of inlet and in the direction of X. Please tell me if I am wrong at some step. Or if there is any other method of applying spin to the nozzle. Thanks in advance

April 25, 2022, 16:05		#4
Syed Wajeeh Member Syed Wajeeh Join Date: Mar 2022 Posts: 56 Rep Power: 4	I am running k-w SST.

April 26, 2022, 04:52		#6
Syed Wajeeh Member Syed Wajeeh Join Date: Mar 2022 Posts: 56 Rep Power: 4	Lucky can you help me in understanding why should I be using periodic conditions and how can I set up these in my problem in ANSYS fluent? I will be very thankful to you

April 26, 2022, 19:38		#8
Syed Wajeeh Member Syed Wajeeh Join Date: Mar 2022 Posts: 56 Rep Power: 4	Got it. Thanks a ton Mate. Stay blessed