Turbulent flows at cryogenic temperatures: a new frontier

Cryogenic helium is of significant value in generating, and studying, the h ighest possible Reynolds and Rayleigh number flows under controlled laborat ory conditions, primarily due to its extremely low value of kinematic visco sity. We consider here critical helium gas and the two liquid phases, heliu m I and helium II. Such flows are already being generated and studied using suitable cryogenic equipment. We outline the current experiments and exist ing proposals for future studies that include gaseous and liquid helium I a nd II.