Oh, sorry my mistake Not theta=x/y in my code but theta=atan(x/y)
2016년 9월 5일 월요일 오후 9시 22분 49초 UTC+9, Jean-Paul Pelteret 님의 말: > > Hi Kyusik, > > r is calculated by "r=sqrt(x^2+y^2) ", and theta is calculated by >> "theta=x/y" > > > At the very least, your definition of theta in the (radial) coordinate > system is incorrect. See the wikipedia page > <https://en.wikipedia.org/wiki/Cylindrical_coordinate_system#Cartesian_coordinates> > for > information as how to convert from Cartesian coordinates to radial > coordinates. > > Regards, > J-P > > On Monday, September 5, 2016 at 2:04:20 PM UTC+2, hank...@gmail.com > <javascript:> wrote: >> >> Hello. >> >> I'm studying step20 >> >> I tried to change the Eq in step20 a little. >> >> So, I change the element of matrix Inverse K >> >> What I changed is like... (in 3D) >> >> K_Inv[0][0]=2*r/(cos(theta)*cos(theta)), >> K_Inv[1][1]=2*r/(sin(theta)*sin(theta)), K_Inv[2][2]=r >> >> r is calculated by "r=sqrt(x^2+y^2) ", and theta is calculated by >> "theta=x/y" >> >> But, as you can expect that ,on the points where |x|<0.0000001 or >> |y|<0.000001, cos(theta) or sin(theta) is almost zero. So, It seems that >> It causes the singularity. >> >> So, At first I tried to change the above 2 element in K_Inv like this... >> >> K_Inv[0][0]=2*r/(cos(theta)*cos(theta)+del) >> K_Inv[1][1]=2*r/(sin(theta)*sin(theta)+del), >> (where del is very small value) >> >> So, the calculation is converged, But the result is not good. Because, on >> the plot, The azimuthal symmetry is broken. even though The Eq I try to >> calculate(Grad-Shaf Eq) is independent of theta. >> >> I attached the result what I made.(What I'm trying to see is pressure >> that is noted by p, I don't need to see u,v or w ) >> >> Is there simple way for me to avoid this singularity error? >> >> Please help me.... >> >> Best Regards. >> >> Kyusik. >> > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
