P. A. Baranov

Numerical Analysis of the Influence of the Depth of a Spherical Hole on a Plane Wall on Turbulent Heat Exchange

A numerical investigation of the influence of the depth of a spherical hole on a plane wall on vortex heat exchange has been carried out within the framework of the multiblock approach to solution of the steady‐ state Reynolds equations closed with the help of Menters zonal model of shear‐stress transfer and the energy equation.

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.

Complex analysis of turbulence models, algorithms, and grid structures at the computation of recirculating flow in a cavity by means of VP2/3 and fluent packages. Part 2. Estimation of models adequacy

A joint testing of the specialized (VP2/3) and universal (FLUENT) packages of applied programs of the hydrodynamic and thermophysical profile is carried out on the basis of the solution of a well-known problem of recirculation flow of a viscous incompressible fluid in a lid-driven square cavity. The Reynolds-averaged Navier — Stokes equations are solved with the aid of implicit factored computational procedures. The adequacy of chosen one-, two-, four-parametric semiempirical differential models of turbulence is analysed in detail.

Controlling the Turbulent Flow Past a Thick Airfoil by Means of Flow Enhancement in Vortex Cells Using Suction from Central Body Surfaces

On the basis of a numerical simulation of the turbulent steady-state flow past a thick airfoil with vortex cells built into the body contour, an unconventional technique for controlling flow separation by means of distributed suction from central bodies embedded in the cells is analyzed over a wide range of Reynolds numbers and suction velocities.

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.

Numerical simulation of the lowering of the drag of a cylinder containing vortex cells with the use of a control system for the turbulent boundary layer

a of eat Using a factorized finite-volume method of solving th Reynolds equations closed by a two-parameter dissipa model of turbulence, we analyze the lowering of the fron drag of a cylinder containing vortex cells when the bound layer is controlled by utilizing provisions for the suction fluid at the central shaft of the cell. Methods of decreasing the drag of a profile by contr ling the turbulent boundary layer by the blowing and suct of fluid in the wall layers are well known in aerodynamic For practice purposes, however, these methods have not developed very far. The growing interest in vortex traps curvilinear surfaces of objects has stimulated the use of tion of the fluid as an instrument for intensifying the flow these traps. In the present study we employ numerical simulati methods to pose and solve the related problem of the in ence of large-scale trapped vortex structures on the turbu flow of an incompressible viscid fluid around an object a on the aerodynamic drag of an object of classic geometry a circular cylinder — for different positions of a circular ce with respect to the center of the cylinder ~Fig. 1a!. The vortex cells under discussion have a central shaft of the s geometry, with provisions for suction of the fluid over th entire contour of the shaft ~Fig. 1b and 1c !. The algorithm that was devised is based on the fin volume method of solving the Reynolds-averaged Navi Stokes equations closed with a high-Reynolds two-param dissipative model of turbulence, utilizing the concept of d composition of the computational region and the genera in substantially different-scale subregions of overlapp multigrid oblique-angle meshes of the same type ~viz., of the O type!. The system of initial equations is written in dive gence form for the increments of the dependent variables covariant components of the velocity and pressure. Such approach is characterized by a more exact representatio the flows through the faces of the computational cells. In the approximation of a source term, which in the ca of the steady-state problem is the right-hand side of the eq tions for the momentum, convective flows were calcula with a one-dimensional counterflow quadratic interpolat scheme, which was proposed by Leonard. 1 It should be noted that the Leonard scheme should be applied not to the c riant but to the Cartesian components of the velocity, oth wise failure of the ‘‘uniform flow’’ test could occur. For this reason, and for convenience of computer programming

Numerical simulation of laminar flow round a cylinder with passive and active vortex cells

Effects involving a reduction in the drag coefficient of a cylinder with passive and active vortex cells of different geometry are analyzed by solving the Navier-Stokes equations by a factorized finite-volume method using the concept of decomposition of the calculation region and using multilevel meshes.

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.

NUMERICAL MODELING OF THE EFFECT OF IMPROVING THE AERODYNAMIC EFFICIENCY OF PROFILES DUE TO THE SUCTION IN VORTEX CELLS

Based on numerical solution of Reynolds equations that are closed using a two-parameter dissipative model of turbulence by the finite-volume method the authors substantiated a technique for decreasing the drag and achieving high efficiency of thick profiles by means of intensification of the flow in vortex cells built into the contour.

Flow control of the semicircular airfoil with a vortex cell at slot suction of air and its blowout into the near wake

In the vicinity of a semicircular airfoil with slot suction of air provided with a 0.2-diameter (chord) vortex cell installed on the backside of the wing, at low speeds and zero angle of attack the pattern of the unsteady separated air-flow undergoes substantial changes, those changes being accompanied with the displacement of flow separation point toward the trailing edge. The slot suction of air and its blowout into the near wake in such an airfoil is organized using a discharge channel with a fan; from this channel, the air jet is discharged into atmosphere tangentially to the airfoil base, with the pressure drop in the fan being equal to twice the pressure head. Under such conditions, the integral force characteristics of the wing show dramatic changes: the lift force, initially being ultra-low negative, becomes positive, and the drag decreases two-fold. The static pressure decreases by two or three times on the upper arch of the profile, and it increases by two times on the lower part of the airfoil, the level of pressure pulsations decreasing by more than ten times.