  The goal of this work is to develop a new universal high order subroutine for
shock boundary layer interaction. First, an effective shock/discontinuity
detector has been developed.The detector has two steps.The first step is to
check the ratio of the truncation errors on the coarse and fine grids and the
second step is to check the local ratio of the left and right slopes. The
currently popular shock/discontinuity detectors can detect shock, but mistake
high frequency waves and critical points as shock and then damp the physically
important high frequency waves.Preliminary results show the new
shock/discontinuity detector is very delicate and can detect all shocks
including strong, weak and oblique shocks or discontinuity in function and the
first, second, and third order derivatives without artificial constants, but
never mistake high frequency waves and critical points, expansion waves as
shock. This will overcome the bottle neck problem with numerical simulation for
the shock-boundary layer interaction, shock-acoustic interaction, image
process, porous media flow, multiple phase flow and anywhere the high frequency
waves are important, but discontinuity exists and is mixed with high frequency
waves. After detecting the shock we can then use one side high order scheme for
shocks and high order central compact scheme for the rest if the shock is
appropriately located. Then a high order universal subroutine for finite
difference method is developed which can be used for any finite difference code
for accurate numerical derivatives.
