function Gamma_circ=CammaCilinder(rho,eta,omega,W)

Re=rho.*omega.*(W.^2)/(4.*eta); %Reynold's number
Gamma_circ=1+((4.*i.*besselk(1,(-i.*sqrt(i.*Re))))./((sqrt(i.*Re).*besselk(0,(-i.*sqrt(i.*Re))))));
