Experimental Investigation of the Effect of Cooling on Near Wake of Circular Cylinder at Mach Number Six

Citation

Ramaswamy, Mathagondapally A. (1971) Experimental Investigation of the Effect of Cooling on Near Wake of Circular Cylinder at Mach Number Six. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/8ZZ8-PC49. https://resolver.caltech.edu/CaltechTHESIS:04152011-112031398

Abstract

An experimental investigation has been conducted to study the near wake of a two-dimensional circular cylinder of 0.2 in. diameter at M_∞ = 6. Mean flow properties were determined from Pitot pressure, static pressure, and hot-wire recovery temperature measurements at free stream Reynolds number of 0.905 X 10^4 and 2.95 X 10^4 for both adiabatic and cooled models, the latter at 0.19 T_o.

The near-wake was laminar for the adiabatic model at both the Reynolds numbers tested. For the cold model, the near-wake was laminar for the lower Reynolds number and transition occurred in the near wake at the higher Reynolds number. The wake shocks, the shear layer edge and the thermal layer edge moved closer to the wake centerline with cooling and with increase in Reynolds number. The base pressure decreased with cooling and the sonic point moved closer to the model on cooling. In the recirculating region, the total temperature distributions exhibited a minimum close to the dividing stream line for all the cases, and the total temperature on the centerline was nearly constant and equal to the value at the rear stagnation point (0.5 T_o for the cold models) indicating that the heat transfer in this region was mainly by convection. The existence of a thin thermal layer on the base was evident for the cold models.

Preliminary experiments on the two-dimensionality of the flow and an emperical formulation for the viscous corrections to the measured Pitot pressure have been included in the Appendices.

Thesis Files