Does pascal's principle apply in a moving fluid?

No.  It is definitely NOT true.  It directly contradicts Bernoulli and Newton.  Pascal's principle is a principle of steady state non accelerating fluid.  There are conditions where some parts of the fluid can be moving and Pascal's principle applies to other parts.  For example two pistons with a pipe connecting them.  The pressure in the pipe can be lower due to its movement but the pressure in both sides can be the same.

Of course once the fluid is moving you get viscous friction so that pressure out < pressure in.  For each direction of motion.  Meaning that in one complete cycle there is hysteresis and energy is lost.  It cannot make a perpetual motion machine.

No, if I am reading and interpreting this correctly. My fluvial geomorphology class was in fall 1993. That was a long time ago. 

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