ENERGY-DISSIPATION IN OSCILLATING FLOW-THROUGH STRAIGHT AND COILED PIPES

The energy dissipation is reported for oscillating flow in U-shaped pi pes with 180 degrees, 540 degrees, and 900 degrees curves at the base of the U. Analysis permits separation of the dissipation in the straig ht and curved portions of the pipe. Using water, water/glycerine mixtu res, liquid nitrogen, and helium gas, the dissipation was measured for fluid flow regimes (Reynolds number, quality factor, and pipe curvatu re) which have not previously been reported. Measured loss in the stra ight portion is compared to numerical solutions using a turbulent quas isteady representation of the wall shear stress. Measured loss in the curved portion is compared to simple theory. The results are applicabl e to thermoacoustic devices. (C) 1996 Acoustical Society of America.