Session BP1 - Poster Session I.
POSTER session, Monday morning, October 23
Exhibit Hall AB, Qu\'{e}bec City Convention Centre
Since measuring flow profiles of a liquid metal is difficult, a full scale water model is used to predict flows in liquid sodium. Water at 50^\circC has the same kinematic viscosity and mass density as sodium at 110^\circC and so the flows in the water model match the flows in the sodium experiment. Laser Doppler Velocimetry (LDV) is used to measure two components of the velocity of suspended particles in the water. An automated traverse positions the laser beam at several points in the sphere to map the two-dimensional velocity field. These data are then fit to spectral components of toroidal and poloidal stream functions which characterize the flow. These spectral components are used in a computer algorithm to determine the growth or damping rates of several modes of the magnetic field. We have identified impeller designs that create flows which can sustain a dynamo and demonstrated the power scaling of the magnetic Reynolds number. We have also investigated the correspondence between the variation of the flow profile on a resistive time scale and the magnetic growth rates for a given impeller design. The results suggest that a flow profile may generate a dynamo even though its average Reynolds number may be insufficient for excitation.