PRESSURE MEASUREMENTS IN SUBCRITICAL PURE SUPERFLUID HELIUM FLOW

The measurement of pressure in He II with flowing superfluid superimposed in a stationary normal fluid was undertaken to demonstrate ideal fluid character of the superfluid below critical velocities. Quantitative agreement with Euler's equation with zero curl is shown with slip-flow boundary conditions. Thus, Bernoulli's equation holds for potential flow and superfluid accelerations occur without dissipation. The method of pressure measurement demonstrates that net forces on an object in non-uniform potential flow can be measured. Copyright © 1968 by the American Institute of Physics.