Q2) a) The tangential velocity profile of the Lamb-Oseen vortex is given by น = 2г (1-e-2/Aut), where r is the radial ordinate, t is time, I' is the circulation and v is the kinematic viscosity. With zero radial velocity the axial vorticity w, in cylindrical coordinates (r, 0) is given by w 1 Drug Tr i) Show that W== 4лvt 2/4vt e ii) Show that the maximum value of ug is at position r given by the expression 1+ e2/Aut 2vt