7.36, §2 PDE Model

• Domain :
• Unknown horizontal perturbation velocity u=u(x,y)
• Hyperbolic
• Two homogeneous initial conditions
• One mixed boundary condition at y=0 and a regularity constraint at
• Constant , where is the Mach angle.

Try a Laplace transform. The physics and the fact that Laplace transforms like only initial conditions suggest that x is the one to be transformed. Variable x is our ``time-like'' coordinate.