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-   -   how to model shock wave generated from detonation? (http://www.cfd-online.com/Forums/fluent/49003-how-model-shock-wave-generated-detonation.html)

Maddy August 13, 2008 08:26

how to model shock wave generated from detonation?
 
Hi folks,

I want to know the impact of a detonation on a distant structure. So i guess i have to model the unsteady propagation of the shock wave generated from the detonation. Can anyone suggest me how to go about it in Fluent?

Thanks in advance,

Regards, Maddy.

Renato Pacheco August 14, 2008 10:21

Re: how to model shock wave generated from detonat
 
first off all, you have to think how you will generate your shock wave and than you have to think about the media of propagation(probably air). you can start thinking in a cube, dont need to be the real situation, and from one side of the cube you make the energy for the propagation of the shock wave.


Maddy August 18, 2008 02:00

Re: how to model shock wave generated from detonat
 
Dear Pacheco, Thanks a lot for the response. Yes, the medium of propagation is air. I have no idea on how to generate the shock wave. Can u kindly suggest me to some reference. I have tried to simulate a hallow cylindrical space with Pressure inlet BC and Pressure outlet boundary in Fluent. But it is diverging all the time. I have used SA model with coupled implicit solver. Kindly suggest me some direction. Thank you, Maddy.

ssixr August 18, 2010 03:04

detonation wave
 
hello maddy,
gud to know tat someone is working on detoantion wave like me....have u succeed in creating detonation wave?


sudhir

Alan September 7, 2010 21:29

I would start by creating the rectangular domain as previously mentioned. You will need to know how far away the origin of the blast wave is from your structure. You will also need to know the initial conditions of the explosion. Then what I do is set up my mesh so I have two domains - the domain under examination (the rectangular domain initially created) and a much smaller domain representing the initiation of the blast wave. This could be spherical or cylindrical - depending on your geometry. You would then patch the blast wave initial conditions into this second domain and run a transient simulation. The blast wave will expand and relax over the course of the simulation, and propagate to your structure under examinaton.

ndabir May 19, 2012 12:22

Hi Maddy,

Did you solved your problem? I am dealing with some similar problem. In fact I am not interested in generation of shock wave but I just want to simulate the propagation of shock wave in air and also in water. I use a high pressure and temperature as inlet (which is a very small sphere) and an atmospheric pressure as outlet (a much bigger sphere). But my results are not reasonable. Could you please tell me what kind of solver did you use and what did you assume for inlet conditions?

hesamking May 6, 2013 17:54

I think the best software for your works are Ls-dyna and Abaqus.
I am a beginner in Ls-Dyna but I know it has the ability of doing all kinds of blast simulation and its interaction with structures or human body.
Also I have seen in several papers the use of Abaqus for this end.
The Ls-dyna has recently included CFD capability to its system.
Just forget about Ansys or Comsol. These gys are much more user friendly and specialized.
Good Luck!
Hesam

sfotovati July 12, 2013 18:05

If you want to check the shock effect, also take a look on Ansys-Autodyn. fr these cases, Explicit-Dynamics works well. You can assign any pressure or velocity, or even an explosive itself, to model the detonation.

hesamking June 24, 2014 19:36

Dear sfotovati,
Actually I am interested to see the flow dynamics of the blast waves. I am currently working with Ls-Dyna that is very similar in nature with Auto dyne and follows an explicit scheme. I have successfully modeled in Dyna but I want to do the CFD which I have to do in CFX or fluent.
any ideas?
Thanks,
Hesam


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