Unsteady Shock Conditions

Frank

Hi Guys, I'm looking at some unsteady transonic flows and was wondering how I would go about determining the shock conditions for such a flow.

The equation I'm solving is 2*f_xt = [ K*f_x - (1/2)*(f_x)^2 ]_x + f_yy

where "f" is the velocity potential and I have used "_x" to denote differentiation w.r.t x; the contents in squared brackets is differentiated by x.

Those of you familiar with the theory will recognise this as the small disturbance equation. I know how to get the shock conditions for a steady flow but am not sure how to find them for the unsteady case - the f_xt term is causing confusion.

Could someone please advise?

Frank