Page:Chandrasekhar - On the decay of plane shock waves.djvu/15



Let ABC denote the pulse at time t. At time t + Δt, A moves to A′ and C to C′ where

where U denotes the shock velocity at time t. During the same time the slope of AB also changes. For at t + Δt the velocity field will be governed by

Accordingly the value of u at the new position B′C′ of the shock front is given by

The increment in u$max$ during the time Δt is therefore given by

Using equation (23) we can rewrite the foregoing equation in the form