Base Flow Topology in Differentially Throttled Linear Aerospike Nozzle

Experimental and numerical investigations are conducted on the base wake flow of two linear aerospike nozzles, created by truncating a common plug contour at 20 percent and 40 percent of its ideal length. The nozzle is subjected to both symmetric and differential throttling. Under symmetric throttling, the base wake flow topology of both aerospikes is numerically analyzed at nozzle pressure ratios (NPR) ranging from 3.7 to 200. Under differential throttling, the flow topology is numerically simulated at a nozzle pressure ratio of 6.5 for various differential throttling levels ranging from 10 to 100 percent, while experimentally tested at NPR = 3.72, 3.78, and 3.82, for differential levels of 6, 10, and 20 percent, respectively. Numerical simulations are performed using the two-dimensional Reynolds-Averaged Navier-Stokes model. Three turbulence models: Spalart-Allmaras, realizable k-epsilon, and SST k-omega are employed to simulate the base flow. Validation against experimental base mean pressure data supports the use of realizable k-epsilon turbulence model, as it predicted base mean pressure within 1.5 percent error. This research explores the variations observed in symmetric and differential base flow configurations.