Hello idnick
This is what I thought Griggs meant, as well the yusmar seems to use the same principal called sonoluminescence.
In my bad picture, as the rotor turns a hole in the rotor approaches an inward "bump"(2) this compresses the fluid in the hole as designated by red dots, the hole then moves past the bump and decompresses as designated by blue dots(1). The magic seems to appear when the frequency of compression/decompression (RPM) is very high, that is why griggs used hundreds of holes, to lower the rotor RPM to managable levels.
The effect they say is based on cavitation or what we know as water hammer, only griggs found it more pronounced at ultrasonic frequencies near 24,000 Hz I believe, google ultrasonic frequencies to get the right number. If you take the number of holes on the circumference of the rotor in one line times RPM divided by 60 you get the number of compressions per second/per hole.Then times this by the number of bumps on the casing for total compressions per second, this is compression cycles/sec equivalent to frequency cycles per second, so 24,000 compressions/second is huge!
This is why I though the yusmar was much easier to build, It can be done your way though I think, and your a much better man than me if you can do it, best regards and please keep us updated.