Transverse Jet Interaction Research Articles

Transverse Jet Interaction with Hypersonic Crossflow I: Experimental and Numerical Investigations

Applications of transverse jet interaction are widespread in hypersonic aircraft systems. In wind tunnel facilities, it is more convenient to perform jet interaction tests with jet fluids of different compositions and with test models of different sizes from those of the actual aircraft. The paper presents a detailed analysis of the transverse jet interaction with hypersonic crossflow by combining the use of both experimental and numerical tools. A hypervelocity ballistic correlation model HB-1, with a sonic jet nozzle, was designed to provide a simplified flowfield for comparison with the simulations. It is found that the temperature and molecular weight of the injectant gas play an important role in the interactions between the hypersonic flow and transverse jet. The applicability of different scaling parameters for this kind of aerodynamic experiment is discussed at the end of this paper.

Numerical investigation of pitch motion induced unsteady effects on transverse jet interaction

Motion-induced unsteady effect is becoming one of the inevitable challenges for the improvement of high-speed and high-maneuvering projectiles performance under a transverse jet control. Therefore, three-dimensional, compressible, unsteady, Reynolds-averaged-Navier-Stokes numerical investigations are performed to illustrate motion-induced unsteady effects on transverse jet interaction. Two pitch motion types, including forced-oscillation and free-response-motion, were chosen to evaluate the potential effects. The current study found that time hysteresis and aerodynamic deviation appear comparing to steady counterparts. Forced-pitch-oscillation data indicate negative interaction-force-amplification-factors at a certain angle of attack while interaction-moment-amplification-factors show an obvious decrease at a relatively high angle of attack. Meanwhile, transverse-jet-controlled free-response-motion data, obtained through coupled CFD/RBD/JET method (a coupled method with CFD (Computation Fluid Dynamics) and RBD (Rigid Body Dynamics) under the control of a transverse jet), visualized positive enhancement of rear jet interaction, as the desired angle can be achieved in less time. Taken together, it is possible that motion-induced unsteady effects on transverse jet interaction may be underestimated and are worthy to be discussed deeply for energy-efficient and flight safety concerns.

Numerical investigation of supersonic transverse jet interaction on CPU/GPU system

The main purpose of this paper is to develop a double-precision parallel algorithm implemented on graphics processing units (GPUs) for quick and accurate numerical simulations of large-scale supersonic transverse jet interaction problems. The finite volume method based on structured grid is considered; the AUSM + UP upwind scheme and the explicit multistage Runge–Kutta method are used for spatial discretization and time discretization, respectively. The turbulent solution is solved by K–ω SST two-equation model. Numerical investigation is performed for a supersonic missile body. Numerical results show that performing calculations on GPU can accurately capture the complex wave structures and vortex structures in the supersonic transverse jet flowfield. For single-GPU implementation, parallel computing can achieve an acceleration ratio of 90 times or more, and four GPU parallel computing can achieve an acceleration ratio of 106–245 times. Thus, GPU parallel computing can achieve a large-scale and efficient solution to supersonic transverse jet interaction problems.

Prediction for the Separation Length of Two-Dimensional Sonic Injection with High-Speed Crossflow

The separation length is an important parameter of transverse jet interaction, which is related to the interaction force, moment, and heating effect. Two-dimensional sonic injection normal to high-speed flow with a turbulent boundary layer is numerically investigated, and the upstream separation length is theoretically predicted. Present numerical study indicates that the separation length is constant as the Mach number increases when the unit Reynolds number is fixed at a range of to for the Mach number greater than 3.50 and smaller than 6.50. Results also indicate that the separation length increases with increasing pressure ratio or increasing slot width as well as decreasing Reynolds number. Based on the high Mach number independence of the separation length and effects of other parameters on the separation length, a combination parameter is proposed and then a theoretical model for the separation length is established. This model can be applied to a wide range of pressure ratios, Reynolds numbers, slot widths, and Mach numbers when the Mach number is greater than 3.50. Upstream separation lengths predicted by the present model are compared with experimental and numerical results, as well as results by the existing model. Results show that separation lengths predicted by the present model agree well with experimental and numerical studies.

Influence of Common Modeling Choices for High-Speed Transverse Jet-Interaction Simulations

Numerical simulations were carried out to determine the sensitivity of results to a variety of geometric and flow parameters commonly employed in high-speed transverse jet-interaction calculations. The configuration consisted of a single circular, flush-wall porthole injector inclined at 30 deg to the freestream in a Mach 4.0 crossflow. Injection was sonic with a jet-to-freestream momentum flux ratio of 2.1. The primary modeling parameters investigated include turbulence model, freestream turbulence intensity, turbulent Schmidt number, and several injector-pipe configurations. The simulations were conducted using the multispecies Reynolds-averaged Navier–Stokes equations with a number of popular turbulence models including the one-equation Spalart–Allmaras model and the two-equation Menter shear stress transport, two-equation realizable , and two-equation nonlinear (cubic) models. The results were found to be very sensitive to both the choice of turbulence model and value of the turbulent Schmidt number. Sensitivities to the boundary conditions imposed on the injector-pipe walls and injector configuration were noted where injection conditions were held constant, but only small variations in results were found where injection mass flow rate was held constant. Finally, variation of the freestream turbulence intensity was found to have almost no influence on the shear stress transport model; however, small effects were identified for the model.