Calibration d'une sonde à film chaud dans de l'eau en rotation

¹ Ing., M.Sc.A. Doc. Ing. en hydraulique (Toulouse). Directeur du Département de Génie civil de la Faculté des Sciences Appliquées. Université de Sherbrooke, Sherbrooke (Qué), Canada.
² Ing. ENSEIHT. Assistant de recherche au Département de Génie civil de la Faculté des Sciences Appliquées. Université de Sherbrooke, Sherbrooke (Qué), Canada.
³ Ing. E.I.M. Doc. Ing. en hydraulique (Toulouse). Professeur adjoint au Département de Génie civil de la Faculté des Sciences Appliquées. Université de Sherbrooke, Sherbrooke (Qué), Canada.

Résumé

For our study of turbulence on moving sand beds behind a dam, we have chosen the system ,which seems to be the most accurate: the hot-wire and hot-film anemometry equipment. We use a DISA constant-temperature anemometer and quartz-coated hot-film probes : wedge-cylindrical and conical probes. The first problem we have to solve is a calibration problem : voltage vs velocity curves. In this paper, we study a new system of calibration. We have built a cylindrical tank turning around its vertical axis. We put some water in and after this water has been accelerated, all the system looks like a rotating solid. The velocity distribution is linear from the center (0) to the wall of the tank (V max). We have studied the drift due to the contamination of the water by dust, the velocity distribution in the water, and the influences of the free surface, the wall of the tank, the temperature... Unfortunately, it is difficult to vary the temperature of the water : we need a thermostatic closed space. This system of calibration seems to be very precise for low and high velocities.