Showing papers on "Drag divergence Mach number published in 2018"
TL;DR: In this paper, a coupling conjugate heat transfer (CHT) approach has been applied to investigate the thermal protection, which takes the heat transfer of structure into consideration, and the influence of the spike length ratio, lateral jet pressure ratio and lateral jet location on the drag and heat reduction performance is analyzed comprehensively.
46 citations
TL;DR: In this paper, a reduction in wave drag is realized through concentrated energy addition in the hypersonic flowfield upstream of the blunt body using an in-house high precision inviscid flow solver.
24 citations
TL;DR: In this article, the influence of ejector rocket parameters on the performance of the combined cycle was analyzed numerically and the simulation results indicated that matching lower altitude with higher flight Mach numbers can increase rocket-based-combined-cycle thrust.
15 citations
12 citations
08 Jan 2018
TL;DR: In this paper, the interaction of on-axis and o-axis laser discharge in front of a hemisphere cylinder in Mach 2.0 is investigated numerically and the energetic effect of the laser discharge on reducing drag is calculated.
Abstract: The interaction of on-axis and o -axis laser discharge in front of a hemisphere cylinder in Mach 2.0 ow is investigated numerically. Details of the physics of the interaction of the laser-induced shock and the heated region with the bow shock and its e ect on drag reduction are included. The energetic eciency of the laser discharge in reducing drag is calculated.
5 citations
25 Jun 2018
1 citations
01 Mar 2018
TL;DR: In this article, a modified method of calculation of the drag coefficient using the lattice Boltzmann method with variable lattice speed of sound was proposed, which is more efficient because the researcher can set the kinematic viscosity of the fluid and the computational grid resolution simultaneously.
Abstract: In this work, we studied the calculation of the drag coefficient using the lattice Boltzmann method with variable lattice speed of sound. The modified method of calculation the drag coefficient that includes the kinematic viscosity dependence was proposed. Calculations were based on the variable lattice speed of sound values that depend on the kinematic viscosity and the computational grid resolution. Shown the influence of the Reynolds number on the flow pattern and on the drag coefficient. The relation between the lattice Mach number and the computational grid resolution have been shown. The influence of the lattice Mach number on the accuracy of the numerical results was studied in detail. Shown that proposed method is more efficient because the researcher can set the kinematic viscosity of the fluid and the computational grid resolution at the same time. Therefore there is an opportunity to control the accuracy of the numerical results and the modeling time.
08 Jan 2018
Posted Content•
TL;DR: In this paper, the effects of a gurney flap on the supercritical NASA airfoil were numerically investigated by solving the two-dimensional Reynolds-averaged Navier-Stokes equations for a range of transonic Mach numbers and angles of attack, using turbulence compressible KW SST model.
Abstract: Effects of a gurney flap were numerically investigated on the supercritical NASA airfoil by solving the two-dimensional Reynolds-averaged Navier-Stokes equations for a range of transonic Mach numbers and angles of attack, using turbulence compressible KW SST model. The height of the gurney flap was selected to be 1.65 percent chord length. A high-resolution mesh was applied to accurately predict the flow field specifically in the vicinity of the airfoil. Below the drag divergence Mach number, the gurney flap has a remarkable influence on the aerodynamic coefficients especially at -1 and 0 degrees angle of attack resulting in 50 percent increase in L over D ratio. At high Mach numbers and angles of attack, Gurney flap loses its effects and the clean airfoil has better aerodynamic performance since it significantly boosts both the pressure and shear drag. It was observed that the gurney flap mitigates the transonic lambda shock on both surfaces of the airfoil. Moreover, it alters the Kutta condition by changing the separation point location at the trailing edge which provides the airfoil more bound circulation and lift force.