CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Main CFD Forum

Impermeable Wall BC Euler Equations

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   January 31, 2013, 13:32
Default Impermeable Wall BC Euler Equations
  #1
New Member
 
Join Date: Dec 2012
Posts: 4
Rep Power: 4
Christian87 is on a distinguished road
Hello,

as the title says I tried to implement an impermeable wall for my 2D Euler equiation Richtmyer FV solver. For validation purposes I'm currently doing calculations for easy cases like the wedge (see pic).

This wedge has an angle of 20 and the freestream Mach number is 3.3. According to the analytical solution (dotted line) there should be a Mach number of 2.75 downstream of the shock.

Unfortunately, I get a Mach number of around 2.3 and I'm blaming my wall bc since the grid should be fine (see pic). If you wonder why I approximated the apex by a parabola, it's only to exclude errors induced by the singularity of the apex. My first grid had an even stronger deviation.

The bcs at the left side is supersonic, respectively supersonic outlet at the right side.

The variables on the wall (j=1) are obtained by extrapolation of the values of the interior

q1bc=q1(i,j+1)
q4bc=q4(i,j+1)

q2bc=q2(i,j+1)
q3bc=q3(i,j+1)

In the next step I transfrom the velocity by using the tangential vector, which I obtain by

t=[x(i+1,j=1)-x(i-1,j=1);y(i+1,j=1)-y(i-1,j=1)];

taking the neighbour wall nodes. After that I norm t and calculate the wall velocity with the dot product (*) as

u_w = (t*[q2bc ; q3bc ]) t

and finally obtain my values for

q2bc=uw(1,1) and q3bc=uw(2,1).

This gave me good results for the Laval nozzle but here for the wedge I think this is the only potential source for the deviation.

Any hints or advice is strongly appreciated. Thank you for reading.


Christian
Attached Images
File Type: jpg edge.jpg (17.6 KB, 7 views)
File Type: jpg wedggrid.jpg (76.0 KB, 10 views)
Christian87 is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Natural convection in a closed domain STILL NEEDING help! Yr0gErG FLUENT 3 June 12, 2013 02:12
Delta form of Heat, Euler and NS equations RameshK Main CFD Forum 3 May 30, 2012 10:41
tmerge utility creates unwanted interface/walls comes in the final mesh dinesh2n@gmail.com OpenFOAM Other Meshers: ICEM, Star, Ansys, Pointwise, GridPro, Ansa, ... 11 January 20, 2012 07:23
UDF for wall slipping HFLUENT Fluent UDF and Scheme Programming 0 April 27, 2011 12:03
Wall functions Abhijit Tilak Main CFD Forum 6 February 5, 1999 02:16


All times are GMT -4. The time now is 04:17.