We present the results of some experiments on the circular hydraulic jump in
normal and superfluid liquid helium. The radius of the jump and the depth of
the liquid outside the jump are measured through optical means. Although the
scale of the apparatus is rather small, the location of the jump is found to be
consistent with the assumption that the jump can be treated as a shock, if the
surface tension is taken into account. The radius of the jump does not change
when going down in temperature through the lambda point; we think that the flow
is supercritical. A remarkable feature of the experiment is the observation of
stationary ripples within the jump when the liquid is superfluid.Comment: Submitted to the proceedings of the 24th International Conference on
Low Temperature Physics. 2 figure
