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Search took 0.00 seconds. Search: Posts Made By: flotus1
Forum: Main CFD Forum August 21, 2013, 02:26
Replies: 26
Views: 4,361
Posted By flotus1
When you say your results are over-predicted,...

When you say your results are over-predicted, what exactly do you mean?
Forum: Main CFD Forum August 3, 2013, 02:38
Replies: 26
Views: 4,361
Posted By flotus1
For NS, i only have a small 1-dimensional...

For NS, i only have a small 1-dimensional (+incompressible +isothermal) code with finite differences.
I guess you will have to go the usual way by debugging your code step by step.
Forum: Main CFD Forum August 2, 2013, 04:39
Replies: 26
Views: 4,361
Posted By flotus1
I am running out of ideas. The way the velocity...

I am running out of ideas.
The way the velocity and temperature boundary conditions are implemented should be correct, provided your adjustments for the temperature are correct.

What happens if...
Forum: Main CFD Forum August 2, 2013, 03:33
Replies: 26
Views: 4,361
Posted By flotus1
Ok, now I get the point for the convergence...

Ok, now I get the point for the convergence criterion with the mass flow discontinuity. I actually misinterpreted the code.
But why do you break the solution process as soon as the mass imbalance is...
Forum: Main CFD Forum August 2, 2013, 02:44
Replies: 26
Views: 4,361
Posted By flotus1
Please post your functions with tags. What...

Please post your functions with tags.

What is this supposed to do?
As soon as the absolute difference for the density is larger than 1e-8 in any element in any time step, the solution is...
Forum: Main CFD Forum August 1, 2013, 18:08
Replies: 26
Views: 4,361
Posted By flotus1
In this case, remove Ac from the formula.

In this case, remove Ac from the formula.
Forum: Main CFD Forum August 1, 2013, 17:29
Replies: 26
Views: 4,361
Posted By flotus1
I imagined something like this, but at least we...

I imagined something like this, but at least we have text now
What is Ac in your expression for the slip velocity?

% surface boundary j=1 with Maxwell Slip Boundary 1st order
for i=2:imax
% for...
Forum: Main CFD Forum July 29, 2013, 17:09
Replies: 26
Views: 4,361
Posted By flotus1
Forgot to mention: In addition (or if your code...

Forgot to mention: In addition (or if your code is stable instead of) of applying under-relaxation, you can also limit the boundary value to the value at the nearest fluid node.
My preferred...
Forum: Main CFD Forum July 29, 2013, 16:58
Replies: 26
Views: 4,361
Posted By flotus1
I assume your code produces reasonable results...

I assume your code produces reasonable results without the Maxwell boundary condition?

I will have a closer look at the code tomorrow.
For now, you could try to apply some under-relaxation to the...
Forum: Main CFD Forum July 23, 2013, 05:21
Replies: 26
Views: 4,361
Posted By flotus1
From what I recall, the non-isothermal slip...

From what I recall, the non-isothermal slip boundary conditions for flat walls read:

u_s^t-u_w^t = \frac{2-\sigma_v}{\sigma_v} \lambda_f \frac{\partial u^t}{\partial n} +\text{neglected term from...
Forum: Main CFD Forum July 22, 2013, 16:20
Replies: 26
Views: 4,361
Posted By flotus1
You have several options for the implementation...

You have several options for the implementation of a first order Maxwell boundary condition.

The easiest (for finite volumes) would be the way Fluent does it. They obtain the wall-normal gradients...
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