Finite volume method was adopted to get the simulation results of aerospike nozzle vehicle model for cold-flow test in wind tunnel which was composed of a linear plug nozzle truncated rate 25% and a lift body.Simultaneously combined with test measurements

outflow effect on flow field structure and performance of linear plug nozzle at different heights (pressure ratio) were presented.It is shown that outflow interference results in excessive expansion of jet and increase of the intensity of lateral flow in linear aerospike nozzle

and also affect the restricted flow around plug bottom.Under the low-altitude flight conditions

there is a serious loss of nozzle performance caused by pressure decrease on plug wall and at the bottom

and a vehicle base drag increase due to the existence of outflow.Under high-altitude flight conditions

the loss of nozzle performance mainly caused by vehicle base drag loss is small

because the pressure on plug wall and at the bottom is no longer affected by outflow.