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Search took 0.00 seconds. Search: Posts Made By: selig5576
Forum: Main CFD Forum May 22, 2017, 11:54
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

Hi Dr. Denaro,

That was a mistake it should be "dt." Furthermore you are correct in saying that it is used in the correction step. Thank you for the immense help you have provided! :).
Forum: Main CFD Forum May 22, 2017, 11:42
Replies: 31
Views: 2,897
Posted By selig5576
Pressure

You are correct I am initializing with zeros, with that said I get correct results. One last question in this thread:

I have read both your papers fairly thoroughly and on the boundaries i=1,nx...
Forum: Main CFD Forum May 19, 2017, 14:19
Replies: 31
Views: 2,897
Posted By selig5576
First iteration

My first iteration gives me the message

Warning: Contour not rendered for constant ZData
> In contourf (line 60)

The first iteration gives a P full of zeros, not NaNs, so I don't think its...
Forum: Main CFD Forum May 18, 2017, 13:26
Replies: 31
Views: 2,897
Posted By selig5576
Singular solution

Hi,

Thank you for the informative replies. I have implemented my Neumann BC for P(2,2). For my first iteration I get a singularity but after the first iteration I don't get any singularities. ...
Forum: Main CFD Forum May 17, 2017, 15:05
Replies: 31
Views: 2,897
Posted By selig5576
P(2,2)

My professor in my first CFD course said to apply P(2,2) in the corner as a degree of freedom. This has to do with the problem of a singular solution from the PPE. In effect it does not have to be...
Forum: Main CFD Forum May 17, 2017, 14:52
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

Hi Dr. Denaro,

Is that not what I'm doing in terms of the code above? In terms of setting u* and v* I am aware there is an issue of accuracy, and to do it correctly I am aware I have to relate u*...
Forum: Main CFD Forum May 17, 2017, 13:29
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

If I understand you correctly, I need to change my indexing for the interior notes from 2:nx-1, 2:ny-1 TO 3:nx-2, 3:ny-2 so I can handle i=2,j=2,i=nx-1,j=ny-1.

The way I am calculating u* and v*...
Forum: Main CFD Forum May 17, 2017, 11:31
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

Hi Dr. Denaro,

I believe I have made a mistake in my code (correct me if i'm wrong.) If I care about the pressure at i=2 and j=2, then at the end points should it not be i=nx-1 and j=ny-1 instead...
Forum: Main CFD Forum May 16, 2017, 16:39
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

Hi,

Is it necessary to compute the pressure along the walls after P has reached convergence given I've already computed the pressure at the walls within the iteration process?.
Forum: Main CFD Forum May 16, 2017, 16:12
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

Hi Dr Denaro,

1. Thats good to know that is supposed to happen in the corners.
2. Interesting
3. I will test it out
4. I am setting the pressure BC's manually as I am merely test the code on...
Forum: Main CFD Forum May 16, 2017, 15:35
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

Hi Dr. Denaro,

That clears up a lot. Using SOR my implementation is


for j=2:ny-1
R(2,j) = (rho/dt)*((1/dx)*(ufs(2,j) - u(1,j)) + (1/dy)*(vfs(2,j) - vfs(2,j-1)));
P(2,j) =...
Forum: Main CFD Forum May 16, 2017, 12:18
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC Rhie-Chow

Hi Dr. Denaro,

I think I am getting incorrect results and I believe it has to do with the way I'm handling the pressure BC. From what I have done in terms of your paper and from lectures here is...
Forum: Main CFD Forum May 12, 2017, 14:40
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

Hi Dr. Denaro,

Thank you for the excellent explanation, I will try both procedures. In terms of the corner boundary conditions, the pressure BC would be handled as follows (following the method...
Forum: Main CFD Forum May 11, 2017, 19:02
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

Hi,

Upon reading your paper, I am curious if you could provide some insight on the differences between your pressure BC and the ones from the slides. The one in your paper has velocity components...
Forum: Main CFD Forum May 9, 2017, 17:16
Replies: 31
Views: 2,897
Posted By selig5576
Pressure BC

Hi Dr. Denaro,

Thank you for the two papers! In terms of the homogenous Neumann BC in Dr. Tryggva's code, is that what the u and v velocity terms are acting as? Upon first read I was quite...
Forum: Main CFD Forum May 9, 2017, 15:38
Replies: 31
Views: 2,897
Posted By selig5576
pressure boundary conditions for collocated grid for Navier-Stokes

Assumptions:
1. Uniform equally spaced grid
2. 2D

When using the Chorin Projection method to solve the incompressible NS on a collocated grid we end up having to solve the following elliptic PDE...
Showing results 1 to 16 of 16

 
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