CONFINED FLOW TEST CASE: FORWARD STEP


 
 

RESULTS AND DISCUSSION






Note : some iteration number are wrong in certain graph, because I loaded data from saved post file, and I think that Iteration number is not part of the post file (.pst),
but part of the model file (.mdl).
 

FIRST RESULTS :

We first present the results obtain without MARS scheme.

Mach Number :

Density :

Pressure :

Velocity (horizontal component) :

The two last graphs allow us to say that Star CD captur a slip lign (see above in the MARS results).

Total temperature :

We present this last graph because physically, the total temperature has to be constant (for us 526.9 K), whereas in our calculation, it is not...
 
 

MARS RESULTS :
 

We now present the results obtained with a restart on previous results as initialisation, and in choosing MARS scheme for the velocity components and the density, and also in forcing the total temperature to be constant (in the thermal models (thermophysical model and properties, liquids and gases) panel, click display options and choose Stagnation enthalpy in the conservation pop-up, and write the total temperature to force in the corresponding box).

First, let us show to you the total temperature... :


 

...Which is nearly constant !

Mach Number :


 

Density :


 

Velocity (horizontal component) :


 

The two above graphs prove us that Star CD has captured the slip lign, because there is a speed discontinuity, whereas the pressure is constant at this place (y=0.9, 1.25<x<2.25).

To precise this phenomenon, we plotted the pressure and the velocity profile for x=1.5 :


 

In blue : the pressure
In green: the velocity magnitude

We can notice that the slip lign is locate as approximately y=0.9, which the symmetric location of the step.

We can also plot the velocity vector in the section x=1.5 :
 

I present also the Mach profile along the bottom boundary.

This graph is a little bit difficult to interprate, but we show it as an example of Graph plotting with Star CD.


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