How to define a circular I.C on carteisan mesh

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

 August 15, 2007, 17:12 How to define a circular I.C on carteisan mesh #1 jinwon park Guest   Posts: n/a I am solving the cylindrical wave propagation problem on the cartesian mesh. Since the mesh is in the cartesian, the defining of cylindrical I.C. is was trivial. I used the smoothed heaviside function as follows FUNCTION heaviside(x,dx,dy,eps) IMPLICIT DOUBLE PRECISION(a-h,o-z) PARAMETER(PI=3.141598d0) IF(x .LT. -eps) THEN heaviside=0.d0 ELSEIF(x .GE. eps) THEN heaviside=1.d0 ELSE heaviside=0.5d0*(1.d0+x/eps+1.d0/PI*sin(PI*x/eps)) ENDIF ENDFUNCTION heaviside It worked well when the discontinuity is not serious(e.g. 1 to 0.1 or 2 to 0.2). However, when I solved a large gradient of a variable(e.g. 500 to 0.1 or 10e9 to 10e4), the initial condition became strange. Even though the smoothed heaviside function gave a smoothed variation like 0.0,0.0001,0.85,1.000, a strange set of I.Cs were created. That is, due to large gradient, a strange sharp hump was observed in the initial condition. I wonder if anyone advice me how to define a circular I.C on a cartesian mesh. Please help me... I need your help. Really.

 August 16, 2007, 11:06 Re: How to define a circular I.C on carteisan mesh #2 rt Guest   Posts: n/a (probably you like to have sharp interface) you can define your cylinderical wave by zero level set of an scaler function (so you sholud define a distance field for initial configuration) and then use either diffusion-less HJ-solvers or use immersed boundary methods (i think S. H. Udaykumar work JCP 05 is suitable for you) for monitoring its propagation.

 August 18, 2007, 09:52 Re: How to define a circular I.C on carteisan mesh #3 John Dongarra Guest   Posts: n/a >Since the mesh is in the cartesian, the defining of cylindrical I.C. is was trivial ?? Do u understand what u say? (poor english !) The famous solution is the level set immersed boundary, i agree with the previous thread, the mentioned paper (there are seris of 3-papers, second one: http://dx.doi.org/10.1016/j.jcp.2005.03.032) is a good ref. complete details is presented (note that this Ref. is very famous and was in 25-top paper list of JCP).

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Turbulent Main CFD Forum 8 December 9, 2012 05:19 aeroslacker Open Source Meshers: Gmsh, Netgen, CGNS, ... 12 January 19, 2012 04:52 Ardalan Main CFD Forum 6 April 17, 2010 23:40 gabrielecfd OpenFOAM 0 December 15, 2009 13:36 Fan Main CFD Forum 10 September 9, 2006 12:24

All times are GMT -4. The time now is 15:06.