No abstract

The present paper focuses on a three-dimensional unsteady turbulent synthetic jet to assess the accuracy of a compressible simulation and some important parameters including the simulations of the actuator, cavity height and Reynolds number. The two-equation SST /k − ω turbulence model is used to predict the flow behaviour. Results show that the compressible simulation case is more accurate than the incompressible one and the dynamic mesh exhibits more reliable results than the mass flow inlet boundary in the compressible simulation. The compressible case displays a delay in the phase of instantaneous velocity for all three Reynolds numbers. Also, the maximum of mean velocity is less than the incompressible case. Moreover, an increase in the Reynolds number leads to an amplification of the peak of mean velocity magnitude. Finally, results demonstrate that a reduction in the cavity height regarding the compressible simulation case causes a reduction in the phase delay and rise in peak of instantaneous velocity magnitude.

The present work provides the computations of unsteady 3D synthetic jet ejected into a quiescent ambient. The SST=k À ! turbulence model is employed for numerical simulations of flow field and the problem is considered under incompressible and axisymmetric assumptions. The pressure-implicit with splitting of operators algorithm is used for coupling of continuity and momentum equations. In order to accurately simulate the synthetic jet actuator, the dynamic mesh method is employed to model the flow field. In different simulations, pressure inlet, pressure outlet and wall boundary conditions at the orifice outlet of the synthetic jet are investigated. Changes in the boundary conditions at the orifice outlet affect the flow field such that mean velocity magnitude is higher for unconfined synthetic jets than confined ones. Moreover, form of vortex rings is dissimilar for confined and unconfined jets. Also, the actuator is modelled with two types of inlet boundary conditions, namely, moving piston and moving diaphragm boundaries. Results show that they have no significant difference and can be used interchangeably.