Inverse boundary value problem for an ekranoplan airfoil with blowing

An inverse boundary value problem of aerodynamics is formulated and solved for an ekranoplan airfoil with blowing through a slot. An airfoil moving with constant velocity along a flat ground surface is considered. The slot is modeled by an annular or straight duct with constant wall velocities. The densities and total pressures in the blown jet and external flow are different. Consequently, the flow velocity is discontinuous across the slip lines. An iterative solution process is developed, and examples of airfoils are constructed for various characteristics of both upper and under-the-wing surface blowing and for various heights. Conclusions are drawn about the effect of blowing parameters on the airfoil geometry and aerodynamics. Copyright © 2004 by MAIK "Nauka/Interperiodica"

Flow about a jet source with a deflector

We suggest a method to solve one of the model problems of aerohydrodynamics, namely, a problem of a flow about a point source, from which a fluid with density and total pressure, different from the corresponding values in the incoming flow enters. The calculations are carried out for various values of the determining parameter; and the data are compared with the known results. We revealed the advantages of the suggested method in comparison with the known ones. © Allerton Press, Inc., 2011

Solution of Nonhomogeneous Helmholtz Equation with Variable Coefficient Using Boundary Domain Integral Method

© 2018, Pleiades Publishing, Ltd. The Boundary Domain Integral Method (BDIM) is applied to the solution of the nonhomogeneous Helmholtz equation with variable coefficient. The analytical formulas for the integrals over the individual boundaries and domain integrals are used to increase the accuracy of the numerical approach. Comparisons of the developed BDIM with the analytical solutions for the homogeneous Helmholtz equation with constant coefficient and the nonhomogeneous Helmholtz equation with variable coefficient are given

Design of a subsonic airfoil with upstream blowing

The problem is solved of designing a symmetric airfoil with upstream blowing opposite to subsonic irrotational steady flow of an inviscid incompressible fluid. The solution relies on Sedov's idea of a stagnation region developing in the neighborhood of the stagnation point. An iterative solution process is developed, and examples of airfoils are constructed. The numerical results are analyzed, and conclusions are drawn about the effect of blowing parameters on the airfoil geometry and the resultant force acting on the airfoil. © 2007 Pleiades Publishing, Ltd

Solution of stokes flow problem using biharmonic equation formulation and multiquadrics method

© 2016, Pleiades Publishing, Ltd.The biharmonic equation formulation of the Stokes flow problem for multiquadrics method is developed. The main advantage of the approach is the iteration free method to find the solution. The numerical method is applied for the problem of steady incompressible fluid flow past a cylinder in the periodic cell of the Kuwabara model. The comparison with known analytical solution and the analysis of absolute and relative errors show that proposed approach gives satisfactory accuracy. The nonmonotonic dependence of the relative errors on the shape parameter typical for multiquadrics method is observed

Calculation and optimization of aerodynamic characteristics of airfoils with jet blowing in the presence of vortex in the flow

© 2016, Allerton Press, Inc.We consider the problem of calculating the ideal non-compressible fluid flow around the airfoil with jet blowing through a channel in the presence of a point vortex with a given circulation in the flow. The effect of the vortex coordinates on the aerodynamic characteristics of the airfoil is investigated and the optimal position of the vortex for maximal lift is found

Approximate method of designing a two-element airfoil

An approximate method is proposed for designing a two-element airfoil. The method is based on reducing an inverse boundary-value problem in a doubly connected domain to a problem in a singly connected domain located on a multisheet Riemann surface. The essence of the method is replacement of channels between the airfoil elements by channels of flow suction and blowing. The shape of these channels asymptotically tends to the annular shape of channels passing to infinity on the second sheet of the Riemann surface. The proposed method can be extended to designing multielement airfoils. © 2011 Pleiades Publishing, Ltd

Flow past a porous cylinder in a rectangular periodic cell: Brinkman and Darcy models comparison

© Published under licence by IOP Publishing Ltd.The problem of the gas suspension flow around a porous cylinder in a periodic rectangular cell within the models of the Stokes - Darcy and the Navier-Stokes - Brinkman using the boundary element and finite volumes method was solved. Streamlines of the carrier phase flow and the air and inertia-less particles capture coefficients of at varying porosities of cylinder medium and periodic cylinder packing were compared

Modeling of fluid flow in periodic cell with porous cylinder using a boundary element method

© 2016 Elsevier Ltd. All rights reserved.The problem of viscous incompressible flow past a periodic array of porous cylinders (a model of flow in an aerosol filter) is solved. The approximate periodic cell model of Kuwabara is used to formulate the fluid flow problem. The Stokes flow model is then adopted to model the flow outside the cylinder and the Darcy law of drag is applied to find the filtration velocity field inside the porous cylinder. The boundary value problems for biharmonic and Laplace equations for stream functions outside and inside the porous cylinder are solved using a boundary elements method. A good agreement of numerical and analytical models is shown. The analytical formulas for the integrals in the expressions for the stream function, vorticity and Cartesian velocity components are obtained. It is shown that the use of analytical integration gives considerable advantage in computing time

Combined method for solving an inverse boundary value problem of aerohydrodynamics for an axisymmetric body

A method was designed for determining the shape of an axisymmetric body from a given velocity distribution in its meridional cross section. The method is based on an iterative process involving the solution to an inverse problem in the plane case and the solution to a direct problem for the body. The iterative process has been implemented in a software program. Numerical computations are presented that illustrate the efficiency of the method. © 2008 Pleiades Publishing, Ltd