According to the theoretical predictions of Yanenko and Vorozhtsov , for a second order scheme contact diffuses as t^1/3. Using a third order code - PPM which behaves as second order near the contact discontinuity , the results were found to be as predicted especially in the diffusing contact case with no shock. These results were extended to shock -contact interaction problem in which the contact discontinuity diffusion is studied after shock passes the contact and within some accuracy it was found that it is indeed the case for this problem also.

Another fact which came out of this study was the different behavior of slow/fast and fast/slow configurations in both diffusing contact and shock contact interaction problem. In case of slow/fast configuration, width of contact discontinuity grows with a power law coefficient of nearly 1/3 whereas in the fast/slow case the width of contact oscillates and doesn't grow much.

Following are the results for various cases:

(a) Diffusing contact without shock

(b) Shock-contact interaction

(1) One dimensional case: Growth rate 1d
(2) Y-invariant case : Growth rate y-invariant 2d
(3) 2 Dimensional case with contact inclined at 10 degrees to vertical : Growth rate 2d case with angle=10
(4) 2 Dimensional case with contact inclined at 30 degrees to vertical : Growth rate 2d case with angle=30