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Vol 8, No 3 (2016)
- Year: 2016
- Articles: 9
- URL: https://journals.rcsi.science/2070-0482/issue/view/12516
Article
Immersed boundary method implemented for the simulation of an external flow on unstructured meshes
Abstract
A method is developed for the numerical simulation of an external flow around solid bodies of unstructured meshes. Several types of boundary conditions are set on the surface of the body, which are simulated by different modifications of the immersed boundary method. The method efficiency is demonstrated on 2D model problems on the computation of subsonic and supersonic flows around a cylinder.
219-230
CABARET scheme’s modification ensuring its high accuracy on local extrema
Abstract
It is demonstrated that the standard flow-variables’ correction required for the monotonicity of the CABARET scheme reduces its accuracy near local extrema. A modified correction of the flows is proposed; it retains the strong monotonicity of the CABARET scheme for Courant numbers r ∈ (0,0.5], and thus ensures its high accuracy near local extrema. The results of the test computations of discontinuous solutions of a nonlinear transport equation are presented; these results illustrate the advantages of the modified scheme.
231-237
On the accuracy of numerical simulation of the boundary layer separation on a finite-width wedge
Abstract
This work is devoted to the validation of modern differential models of turbulence for the calculation of separation in a supersonic flow around the compression wedge. Use is made of the data of experiments for the 25° wedge made by A.A. Zheltovodov at the Khristianovich Institute of Theoretical and Applied Mechanics (ITAM), Siberian Branch (SB), Russian Academy of Sciences (RAS). These data are compared to the results of the three-dimensional and two-dimensional calculations by the use of several differential models of turbulence. A modification of the SST model is proposed that yields an improvement in the quality of the description of the separation zone. The three-dimensional structure of the separation on the wedge is analyzed.
238-248
Application of artificial viscosity for suppressing the carbuncle phenomenon in Godunov-type schemes
Abstract
A new approach for solving the carbuncle phenomenon that occurs in Godunov-type schemes when applied to hypersonic flow simulations is proposed. The approach suppresses carbuncle-instability by additional dissipative terms in the form of the right-hand side of Navier-Stokes equations, but with artificial instead of molecular viscosity. The efficiency of the proposed approach is demonstrated on several test problems.
249-262
Numerical studies of specific features of the transonic flow reconstruction on a hammerhead model
Abstract
The results of the numerical studies of transonic flow reconstruction occurring with an increase in the free stream Mach number on a hammerhead cone-cylinder body with a small break angle in the generatrix are presented. A turbulent flow regime is considered. The Reynolds equations with different turbulence models are used. The numerical results are compared to the experimental data and the results of the calculation using the Euler model.
263-273
Numerical simulation of the transonic turbulent flow around a wedge-shaped body with a backward-facing step
Abstract
A fully three-dimensional near-wall complex turbulent flow around a wedge-shaped body with a backward-facing step is considered with the transonic flow regime (Mach number M = 0.913) at the Reynolds number Re = 7.2 × 106. The technology of the numerical simulation of problems of the class under study is represented in detail. A series of preliminary auxiliary calculations is carried out for choosing the optimal computational algorithm. The numerical results of the problem simulation based on the eddy-resolving hybrid RANS-LES approach IDDES are finally given for the full configuration. The validity of the results obtained is confirmed by comparing them to the corresponding experimental data.
274-284
Correlation between the discontinuous Galerkin method and MUSCL-type schemes
Abstract
The discontinuous Galerkin method is compared with MUSCL-type schemes. The description and the analysis of the schemes are presented by using the solution of the linear advection equation as an example. The techniques for a generalization of these schemes to the case of solving nonlinear and multidimensional problems are considered. The correlation between the discontinuous Galerkin method and MUSCL-type schemes, as well as their distinctive features, are revealed. The criteria of the accuracy and the efficiency of the schemes as applied to problems of various classes are discussed.
285-300
The data from the numerical investigation of turbulent combustion in jet flows
Abstract
The data from the numerical calculations are represented for free subsonic and supersonic turbulent jets subject to chemical reactions (combustion) of the flowing components. The calculations are carried out using averaged Navier–Stokes equations with various turbulent-viscosity models (k–ε, SST, Secundov model) and the large eddy simulation (LES). The Magnussen model and the Zeldovich model are regarded as turbulent combustion models. The calculation data are compared with the experimental data.
301-308
Numerical simulation of aerodynamic and acoustic characteristics of a ducted rotor
Abstract
This work is devoted to the numerical simulation of the problem about a rotor rotation in a duct in a noninertial reference frame based on the Euler equations. The configuration is a model of a tail rotor of a helicopter. The calculations were carried out using highly accurate EBR schemes on unstructured tetrahedral meshes with the variables determined at the nodes. The numerical results on the aerodynamic forces, as well as the intensity and direction of the acoustic radiation in the far field, are presented and analyzed.
309-324