- **Main CFD Forum**
(*https://www.cfd-online.com/Forums/main/*)

- - **How to define a circular I.C on carteisan mesh
**
(*https://www.cfd-online.com/Forums/main/13962-how-define-circular-i-c-carteisan-mesh.html*)

How to define a circular I.C on carteisan mesh
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. |

Re: How to define a circular I.C on carteisan mesh
(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. |

Re: How to define a circular I.C on carteisan mesh
>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). |

All times are GMT -4. The time now is 08:07. |