artvisc.m

various matlab programs to slove various problems

function [Kupw,rhsbc] = artvisc(Nx, h, nu, beta)
Peclet=0.5*h*abs(beta);
for i=2:Nx
   dd(i-1)=(Peclet(i-1)+Peclet(i))/h;
   if i > 2
     ld(i-2)=-Peclet(i-1)/h; 
   end
   if i < Nx
     ud(i-1)=-Peclet(i)/h; 
   end
end
Kupw=spdiags([[ld 0]',dd',[0 ud]'],-1:1,Nx-1,Nx-1);
rhsbc = - [Peclet(1)/h, Peclet(Nx)/h]; 
return