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hedy March 23, 2007 03:22

CFD code for supersonic flows
I am working in the field of supersonic fluid dynamics. The main topics contain: 1. the supersonic nozzle design 2. supersonic flows simulation (The important parameters are pressure, velocity, density and so on.) 3. supersonic nozzle optimization

Can anybody give me the idea about which code can work well with these topics?

A.S. March 23, 2007 05:52

Re: CFD code for supersonic flows

Andy R March 29, 2007 15:44

Re: CFD code for supersonic flows
Try Gasp from Aerosft. Note no O in soft! Came out of NASA/Vulcan heritage.

Question for A.S - what mach number have you pushed Star-CCC to? My experience with star predates CCM and going much past transonic in V3.X was not too easy.

Currently using GASP and FLUENT. We push FLUENT upto about mach 3-4 . GASP we can go as high as 20, but it isn't alll that robust with subsonic flows.

My2cents - Andy

A.S. March 30, 2007 06:22

Re: CFD code for supersonic flows
Mach 20 Nozzle

Bart Prast April 2, 2007 10:05

Re: CFD code for supersonic flows
Compressible flow -> use CFX with coupled solver. Will give you an answer in no time. But for for flows beyond Mach 3-4 I would not use the major commercial codes. Use density based codes instead with proper shock handling. You might want to write your own Euler solver (with boundary layer displacement thickness correction). It's fast, cheap and may help you to design your particular nozzle fast. Do this only for relatively simple geometries.


Valintino April 3, 2007 13:37

Nice site
Hello, Your site is great. Regards, Valintino Guxxi

Bart Prast April 5, 2007 06:34

Re: Nice site
Which site? CFD-online?

Andy R April 9, 2007 11:45

Re: CFD code for supersonic flows
AS, Did your Mach20 Nozzle include any chemistry? Temperature dependent properties? What total temp/pressure did you have upstream of the nozzle? Is this a solution you could share?

We would be very interested to see a high end commercial code (as opposed to a NASA derivitive product) that can operate in that flow regime.

Thanks - Andy R

EJAZ April 10, 2007 15:19

Re: CFD code for supersonic flows
Question: How to choose a time step? Answer: An optimal time step depends on the used mathematical model. General recommendations are as follows:

Solid Material: take the time step as one tenth of the body heating time: , where l is the characteristic size of the body, is the coefficient of thermal diffusivity.

Laminar Fluid, k-e turbulence model, Weak Compressible Fluid, Combustion Model: take the time step as one tenth of the ratio of the characteristic length of the domain in the steramwise direction to the characteristic flow speed.

Free Surface: the time step is determined by the condition that the Courant number equals 1.

Full compressible: the time step must provide fast convergence of the pressure calculations. The initial step is specified similarly to Laminar Fluid, k-e turbulence model etc. If the pressure calculations diverge, decrease the time step. If conjugate heat transfer is concerned and a steady solution is sought, different time steps can be defined in the fluid and solid body in order to accelerate convergence to the solution. Select the Use Own Time Step and Step check boxes on the Enthalpy tab in the Method parameters window of the solid sub-region. Enter the CFL number or the global time step in the Step dialog box. Normally, the time step in solid body is higher than that in fluid.

sandeep April 16, 2007 10:56

CFD code for supersonic nozzle design
Can anybody send code for supersonic nozzle design using moc for M 3.5?

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