simulation supersonic external flow arround the missile diverge!!

raminostadi · April 13, 2018, 01:34

hello everyone .I'm working on shock wave behind the rocket (missile) for one month . I simulate supersonic flow arrond the rocket. my conditions are:

mesh : I try for improving mesh quality but inflation layer error stair mesh.

pressure far field: Mach=2.6 , static pressure=1171 pa
, Temperature= 227k
rocket surface: wall , operation pressure=zero pascal
ideal gas for air , sst-kw model.

solution initialization: standard from far field.

solution method: both density based and pressure based.

when I run density based; this errors ocure :
absolute pressure and temperature limite to 1. I change limits and change courant number, I change relaxation factors but solution diverge again.

when I run pressure based; continuty residuals increase to 1000 and solution diverge, I change relaxation factors and solution diverge again.

I'm not sure but I think the problem is my mesh quality because I can't inflation layers around the rocket. I really try for improving mesh quality but only I can change mesh sizing.

I'm really tired. please help me. if one of you can solve my problem, I will send you my Ansys file to your email.

please help me.

kiran · April 13, 2018, 05:18

change the operating pressure to 101325 Pa , are you working on 2D or 3D model ? share pictures mesh cross sections.

raminostadi · April 14, 2018, 12:13

I'm working on 3d model. Ithink, I should set operation pressure to zero for supersonic flow. I share my mesh.

I solve my problem by changing URF. but continuty residual reach 0.8 slowly. after that it remain constant (I share picture) . I want to export pressure result to mechanical for fsi, then continuty converging is very important for me.

thank you.

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April 13, 2018, 01:34	simulation supersonic external flow arround the missile diverge!!	#1
raminostadi Member ramin Join Date: Jul 2016 Posts: 41 Rep Power: 9	hello everyone .I'm working on shock wave behind the rocket (missile) for one month . I simulate supersonic flow arrond the rocket. my conditions are: mesh : I try for improving mesh quality but inflation layer error stair mesh. pressure far field: Mach=2.6 , static pressure=1171 pa , Temperature= 227k rocket surface: wall , operation pressure=zero pascal ideal gas for air , sst-kw model. solution initialization: standard from far field. solution method: both density based and pressure based. when I run density based; this errors ocure : absolute pressure and temperature limite to 1. I change limits and change courant number, I change relaxation factors but solution diverge again. when I run pressure based; continuty residuals increase to 1000 and solution diverge, I change relaxation factors and solution diverge again. I'm not sure but I think the problem is my mesh quality because I can't inflation layers around the rocket. I really try for improving mesh quality but only I can change mesh sizing. I'm really tired. please help me. if one of you can solve my problem, I will send you my Ansys file to your email. please help me.

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April 13, 2018, 05:18		#2
kiran Member kiran Ambilpur Join Date: Jun 2010 Location: India Posts: 50 Rep Power: 15	change the operating pressure to 101325 Pa , are you working on 2D or 3D model ? share pictures mesh cross sections.

April 14, 2018, 12:13		#3
raminostadi Member ramin Join Date: Jul 2016 Posts: 41 Rep Power: 9	I'm working on 3d model. Ithink, I should set operation pressure to zero for supersonic flow. I share my mesh. I solve my problem by changing URF. but continuty residual reach 0.8 slowly. after that it remain constant (I share picture) . I want to export pressure result to mechanical for fsi, then continuty converging is very important for me. thank you. geometry.JPG Capture 1 .JPG Capture 3.JPG Capture2.jpg Capture5.JPG