Shock Reduction through Opposing Jets—Aerodynamic Performance and Flight Stability Perspectives

Abstract

In this research paper, investigations of counter flow (opposing) jet on the aerodynamic performance, and flight stability characteristics of an airfoil with blunt leading-edge in supersonic regime are performed. Unsteady Reynolds-Averaged Navier-Stokes ( U R A N S ) based solver is used to model the flow field. The effect of angle of attack ( α ), free-stream Mach number ( M ∞ ), and pressure ratio ( P R ) on aerodynamic performance of airfoil with and without jet are compared. The results indicate that the opposing jet reduces drag from 30 % to 70 % , improves the maximum lift-to-drag ratio from 2.5 to 4.0, and increases shock stand-off distance from 15 % to 35 % depending on flow conditions. The effect of opposing jet on longitudinal flight stability characteristics, studied for the first time, indicate improvement in dynamic stability coefficients ( C m q + C m α ˙ ) at low angles of attack. It is concluded that the opposing jet can help mitigate flight disturbances in supersonic regime.

Review of wave drag reduction techniques: Advances in active, passive, and hybrid flow control

“…165 A regular diamond-shaped pattern was observed due to the formation of weak expansion and compression waves (reflected waves), which makes LPM mode unstable as shown in Figure 8(a). 166 The recirculation regions are slim and remain attached to jet boundary. 167 On further increase in PR, the length of the jet increases retaining its diamond-shaped pattern until PR reaches its critical value ( PR cr ) where the jet achieves its maximum length.…”

Modeling and Analysis of Shock Reduction through Counterflow Plasma Jets

“…A 2D and 3D validation for all the geometries (shown in Figure 2(a)) are followed in this research is a three-step procedure. e grid strategy (Figure 2(b)) for truncated cone and an airfoil remains the same as in [42]. is work emphasized the comparison of the counterflow conventional (nonplasma) jet and hot gas (ionized gas or plasma) ejection.…”

“…is work emphasized the comparison of the counterflow conventional (nonplasma) jet and hot gas (ionized gas or plasma) ejection. Hence, the air jet ejection case validation is already discussed in [42] with the experimental data of Eugene [15]. Now, in the case of plasma, the computational setup for generated plasma inside the nozzle is validated with the available experimental data of Liu [43].…”

“…e airfoil has a blunt leading edge with a chord length of 1 m. e jet diameter is taken as 5 mm at the leading edge. However, the meshing strategy remains the same (Figure 10(a)) as used in [42] except the installation of the plasma nozzle (Figure 10(b)). In a fully structured mesh with boundary conditions, pressure inlet, pressure outlet, and pressure far-field are selected to model the flow structure.…”

“…A few studies exist in which elliptical bodies were used for drag reduction using a counterflow jet technique such as by Love et al [15]. Recent research was carried out by Rashid et al [42] in which a conventional counterflow jet was implemented on an airfoil (NACA 0012) nose in supersonic flow to minimize drag. e present investigation focus on the understanding of counterflow ionized gas (plasma jet) in a supersonic regime.…”