A. G. Sudakov

Modeling the increase in aerodynamic efficiency for a thick (37.5% chord) airfoil with slot suction in vortex cells with allowance for the compressibility effect

The Reynolds equations closed using the Menter shear-stress-transfer model modified with allowance for the curvature of flow lines have been numerically solved using multiblock computational technologies. The obtained solution has been used to analyze subsonic flow past a thick (37.5% chord) airfoil with slot suction in circular vortex cells intended for the Ecology and Progress (Ekologiya i Progress, EKIP) aircraft project in comparison to a distributed (from the central body surface) suction at fixed values of the total volume flow rate (0.02121) and Reynolds number (105) in a range of Mach numbers from 0 to 0.4. This analysis revealed a significant (up to tenfold) decrease in the bow drag (determined with allowance for the energy losses) and a large (by an order of magnitude) increase in the aerodynamic efficiency of the thick airfoil containing vortex cells with slot suction, which reached up to 160.

Analysis of extremal lift behavior of a semicircular airfoil in a turbulent airflow at a near-zero angle of attack

The experimentally discovered phenomenon of lift drop for a semicircular airfoil in a turbulent airflow at a near-zero angle of attack has been numerically analyzed with multiblock computational technologies using a shear-stress-transfer model modified with allowance for the curvature of flow lines.

Expansion of the range of critical mach numbers during control of transonic flow past a thick (20% chord) MQ airfoil with slot suction in a circular vortex flow

The Navier-Stokes and Reynolds equations have been numerically solved by a factorized finite-volume method. The Reynolds equations were closed using the Menter shear-stress-transfer model modified with allowance for the curvature of flow lines. The obtained solution has been used to confirm expansion of the range of critical Mach numbers during modeling of a nonstationary flow past a thick MQ airfoil with slot suction in circular vortex cells.

Modeling the effect of head drag reduction for a cylinder with a protruding disk at high mach numbers

Various approaches to modeling super- and hypersonic turbulent airflow past cylindrical bodies with a nontraditional nose in the form of a protruding rod-supported disk have been compared. Aeroballistic experiments on a light-gas propulsion setup were combined with wind tunnel tests and numerical simulations using VP2/3 program package based on multiblock computational techniques and a model of shear stress transport with flow-line curvature corrections. The phenomenon of the head and wave drag reduction for the stepped body is analyzed at high Mach numbers (up to 10) and variation of the supporting rod length under conditions of existence of the frontal flow separation zone.

Simulation of turbulent flow around a tear-shaped body with a tapered flare

The axisymmetric flow around a tear-shaped body with a flare is analyzed by solving the continuity equation, Reynolds equations (closed with the Menter model of shear stress transport), and energy equation. In the solution, a factorized multiblock finite-volume technique embedded in a VP2/3 program package is used. Numerical estimates are compared with aeroballistic tests of a model. Direct-shadow flow patterns are recorded and the trajectory parameters are calculated with the aim of determining the aerodynamic drag at a close-to-zero angle of attack. Interferograms of the axisymmetric flow around the body (M = 4.35) are also taken. The calculated and experimental data for the flow density transverse (radial) distribution are in good agreement. Agreement between the calculation and experiment in the drag coefficient at a close-to-zero angle of attack is also observed.

Estimation of the lifetime of a trapped vortex in a circular cavern on a semicircular airfoil streamlined at a zero angle of attack after switching off slot suction

The restructuring of the periodic structure of a turbulent streamline for a semicircular airfoil at a zero angle of attack with a system of slot suction from the circular cavern switched off is calculated. Multiblock numerical methods are applied for solution of Reynolds-averaged nonstationary Navier–Stokes equations closed using the modified shear-stress transfer model taking into account flow line curvature. The lifetime of a trapped vortex in a circular cavern is estimated.

Modeling an increase in the lift and aerodynamic efficiency of a thick Göttingen airfoil with optimum arrangement

The Reynolds equations closed using the Menter shear-stress-transfer model modified with allowance for the curvature of flow line have been numerically solved jointly with the energy equation. The obtained solution has been used to calculate subsonic flow (at M = 0.05 and 5° angle of attack) past a thick (24% chord) Göttingen airfoil with variable arrangement of a small-sized (about 10% chord) circular vortex cell with fixed distributed suction Cq = 0.007 from the surface of a central body. It is established that the optimum arrangement of the vortex cell provides a twofold decrease in the bow drag coefficient Cx, a threefold increase in the lift coefficient Cy, and an about fivefold increase in the aerodynamic efficiency at Re = 105 in comparison to the smooth airfoil.

Controlling the Flow past a Semicircular Airfoil at Zero Angle of Attack Using Slot Suction in One or Two Vortex Cells for Attaining Extremal Lift

Calculations using multiblock computational technologies and a model of shear-stress transport modified with allowance for the curvature of streamlines in turbulent airflow were performed at a zero angle of attack for a semicircular airfoil containing one or two surface vortex cells with slot suction. The results showed evidence of stabilization of a nearly undetached flow and attainment of an extremal lift of Cy = 5.2 and a lift-to-drag ratio of K = 24 with allowance for energy losses for suction in the vortex cells.