VOLUMETRIC MEASUREMENT OF LOCAL VORTICITY VECTORS BY OPTICAL PROBE

THE VORTICITY OPTICAL PROBE (VOP) IS A RECENTLY DEVELOPED TECHNIQUE WHICH USES MICROSCOPIC CLEAR SPHERICAL PARTICLES CONTAINING EMBEDDED PLANAR REFLECTIVE CRYSTALS TO SAMPLE THE LOCAL VORTICITY OF A LIQUID FLOW IN WHICH THEY ARE SUSPENDED. LASER LIGHT REFLECTIONS FROM THE PARTICLES, DETECTED EXTERNALLY TO THE FLOW, HAVE BEEN USED IN THE PAST TO DETERMINE ONE OR TWO COMPONENTS OF A SINGLE SPHERE'S ANGULAR VELOCITY SECTOR, WHICH IS EQUAL TO HALF THE LOCAL VORTICITY. WE PROPOSE TO DEVELOP OPTICAL TECHNIQUES WHICH WILL ENABLE SIMULTANEOUS MEASUREMENT OF ALL THREE VORTICITY COMPONENTS AT MANY IDENTIFIABLE POINTS OVER A LARGE VOLUME OF THE FLOWFIELD. SIMULATIONS OF ROTATIONAL FLOWS WILL BE USED TO EVALUATE THE FEASIBILITY OF THE PROPOSED APPROACH.