Subject: The CFD Demo

From: Saleh Elmohamed <[email-masked]>
Date: Thu, 5 Nov 1998 15:39:09 -0500 (EST)

Bryan,

Here is a summary. Modify or add to it if you wish. If you
like more details, let me know and will send some more:

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                   Computational Fluid Dynamics :
             2-D Inviscid Flow, Airfoil, and Elliptic Flow
                            Simulations

This CFD system simulates a 2-D inviscid flow through an axisymmetric
nozzle, flow over airfoil as well as an elliptic flow. The simulation
yields contour plots of all flow variables, including velocity
components, pressure, mach number, density and temperature. The plots show
the location of any shock wave that would reside in the nozzle or at the
tip of the airfoil. 
The simulation centers around finding the steady state
solution to the 2-D Euler equations. For this, it uses a 4-stage
Runge-Kutta time-stepping algorithm and a finite volume central-difference
method to come up with the solution. At each stage, the residual is
multiplied by a difference value. Generally, this gives a bit more
accurate results since it goes over more than one stage. A numerical
dissipation model is employed to dampen any spurious oscillations and
prevent the solution from blowing up in the presence of shock waves (see
James et al. 81). The dampening order is set by computing the even
derivatives (i.e. 2nd and 4th) and then setting the order proportional to
this.
The flow is from left to right across the nozzle or over the
airfoil. To see the flow through, 'tuft' and 'grid' keys were
added. The flow shown here is transonic and the system can be adjusted to
have either a subsonic or a supersonic flow.

References:

1. "Numerical Solutions of the Euler Equations by Finite Volume Methods
Using Runge-Kutta Time-Stepping Schemes," A. Jameson, W. Schmidt, and E.
Turkel, paper no: AIAA-81-1259, AIAA 14th Fluid and Plasma Dynamics
Conference, June 23-35, 1981, Palo Alto, CA, USA.

2. Monograph in CFD, T. Q. Dang, Dept. of Mechanical, Aerospace and
Manufacturing Engineering, Syracuse University, Syracuse, NY, USA, 1997.

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From: Bryan Carpenter <[email-masked]>
Date: Thu, 5 Nov 1998 15:43:31 -0500 (EST)

Thanks

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