The Skval concept was to launch at high speed and then sweep at terminal range. It was NOT the other way around.
BTW the USN tested high speed "supersonic" torpedoes in the mid 60's - some 30 years before the Sovs/Russians. It was headed up by Dr John Sirmalis
There's a reason as to why "supersonic" torpedoes have limited utility.....
You are correct, I found the paper.
The paper was part of a Seminar by Akash Mankar on "Cavitation and Supercavitation" discussed the Shkval and other cavitation weapons being researched.
It states, as you also point out, that:
"The Shkval is fired from the standard 533-mm torpedo tube at a depth of up to 328 ft (100 m). The rocket-powered torpedo exits the tube at 50 knots (93 kmh) and then ignites the rocket motor, propelling the weapon to speeds four to five times faster than other conventional torpedoes. The weapon reportedly has an 80 percent kill probability at a range of 7,655 yd (7,000 m).
The torpedo is guided by an autopilot rather than by a homing head as on most torpedoes. The initial version was unguided. However, the Russians have indicated there is a homing version that starts at the higher speed but slows and enters a search mode."
The paper also describes Supercavitating projectiles used to clear mines. Such as RAMICS (Rapid Airborne Mine Clearance System) using 20m projectiles that are stable in both air and water, and AHSUM (Adaptable High-Speed Undersea Munitions ) Adaptable Kinetic Kill projectiles. Sort of an underwater Phalanx system.