Present paper investigates the numerical solution of two-dimensional unsteady COMPRESSIBLE Navier-Stokes equations by a new scheme based on the finite volume method. Kinetic Energy Preserving (KEP) scheme is introduced for solving the supersonic and Transonic external COMPRESSIBLE FLOW field on very fine grids (with a number of cells of the order of the Reynolds number) without artificial dissipation terms even in place of shock waves. It should be noted that the solution of FLOW field with this scheme in this range of speed, is presented for the first time.By discretization of the governing equations based on KEP scheme and elimination of dissipative effects, the Direct Numerical Simulation (DNS) of the FLOW is possible. The results of this solution for supersonic FLOW over flat plate and Transonic FLOW over the airfoil at low Reynolds numbers show that the KEP method can be presented stable and non-oscillatory solution by no artificial dissipation even in areas with shock waves. Therefore, the KEP method can be used for DNS of turbulent FLOWs (without a modeling the turbulence phenomena itself).

A Finite Volume-Lattice Boltzmann Method (FVLBM) for simulation of VISCOUS laminar COMPRESSIBLE FLOWs in 2-D structured curvilinear coordinate system has been developed. In the present study, validation of the presented software and accuracy assessment of four new 2D lattices D2Q9L2, D2Q13L2, D2Q17L2 and D2Q21L2 based on increasing discrete velocities of lattice has been studied and the optimum lattice has been introduced. The presented LBM has developed using new method of circular function idea instead of expansion or correction of Maxwelian function for evaluation of equilibrium distribution functions. Moreover, in order to capture discontinuities in the FLOW field, 3rd order MUSCL scheme has been implemented for approximation of convective term. The laminar COMPRESSIBLE VISCOUS FLOW over the NACA0012 airfoil has been simulated in the curvilinear coordinate system for two angle of attacks, 0 and 10 Deg. The obtained results have been compared with validated N.S. solutions. Although the results have desirable accuracy in comparison of those of the N.S. solutions, limitation of the presented method and results assessment obtained by the different lattices have been investigated.

The study of COMPRESSIBLE FLOW plays a fundamental role in the design of heat exchangers at high temperature and pressure. COMPRESSIBLE FLOW is used to design the aerodynamic structure, engines, and high-speed vehicles. In view of these utilities, this paper is deliberated to acquire the analysis of the unsteady COMPRESSIBLE FLOW of a VISCOUS fluid through an inclined asymmetric channel with thermal effects. Special attention is paid to convective heat transfer with impact of VISCOUS dissipation, source/sink, and joule heating effects. In addition, thermal FLOW is analyzed through slip boundary conditions. The current problem is modeled through the laws of energy, momentum, and mass with the help of a fluid’s response towards compression. As a result, the coupled nonlinear partial differential equations are obtained, which are investigated through a well-known numerical approach, the explicit finite difference method. The study examines impact of several parameters on the FLOW rate, velocity, and temperature with the help of graphical representations. The behavior of FLOW rate is intended to change with time.

Existing solutions of the problem of axisymmetric stagnation-point FLOW and heat transfer on either a cylinder or flat plate are for inCOMPRESSIBLE fluid. Here, fluid with temperature dependent density is considered in the problem of axisymmetric stagnation-point FLOW and heat transfer on a cylinder with constant heat flux. The impinging free stream is steady and with a constant strain rate, `k. An exact solution of the Navier-Stokes equations and energy equation is derived in this problem. A reduction of these equations is obtained by use of appropriate transformations introduced for the first time. The general self-similar solution is obtained when the wall heat flux of the cylinder is constant. All the solutions above are presented for Reynolds numbers, Re=`ka2/2u, ranging from 0.01 to 1000, selected values of compressibility factors, and different values of Prandtl number, where a is cylinder radius and u is the kinematic viscosity of the fluid. For all Reynolds numbers and surface heat flux, as the compressibility factor increases, both components of the velocity field, the heat transfer coefficient and the shear-stresses increase, and the pressure function decreases.

In this paper, oscillations of a thin high flexible strip attached to a three-dimensional body in VISCOUS subsonic FLOW were simulated. The aim is to analyze the interactions of fluid and structure using a proper coupling algorithm that can couple the fluid and structure solvers and provide the proper data exchange between them. A computational fluid dynamics solver is used for fluid FLOW simulation and Euler-Bernoulli cantilevered beam model is used for structural analysis. For analyzing the fluid-structure interaction, iterative partitioned coupling algorithm is used for interrelation and data exchange between structure and fluid. Then, the results of vibration characteristics including the amplitude and frequency and forces and moments variations are presented with respect to different bending stiffness and strip masses. The simulation is done in 2D and 3D conditions which 3D case is for a cylinder and flexible strip attached to the bottom of the body. Results show that the developed framework captures the physics of fluid-structure interaction successfully. Also, parametric study shows that for the flexible thin strip attached to the end of the body in the specified regime of FLOW, three deformation types consist of static deformation, stable oscillations, and chaotic unstable oscillations will occur based on the strip characteristics.

This research explores and compares the AUSM scheme family based on COMPRESSIBLE, steady, VISCOUS, and inviscid axisymmetric FLOWs in a finite-volume method-based and unstructured data storage grids code. When the effects of side-velocity are taken into account, axisymmetric FLOWs can be considered a three-dimensional problem in the longitudinal plane, as a result, there is a considerably decreased number of computations required compared to computations in three dimensions. The most important and latest modifications of the AUSM-family were developed to identify more efficient methods in the AUSM-family in terms of accurate prediction of the axisymmetric FLOW field in internal and external axisymmetric FLOWs, VISCOUS (inviscid), and high-speed FLOWs with shock waves characteristics. The novelty of this investigation is the assessment and comparison done on the AUSM-family in resolving the COMPRESSIBLE axisymmetric FLOW field, which has received less attention in prior studies. The studies determined that the AUSM+M method performs better against a strong shock wave than other methods investigated in this research. According to the modifications made in this scheme, unlike other methods, there are no wiggles in the regions mentioned earlier. Furthermore, it is discovered that the AUSM+M method had a higher rate of convergence than the AUSM+ and SLAU approaches. In addition, the AUSM+M scheme is distinctive from other techniques in VISCOUS FLOWs because it produces the minimum kinetic energy dissipation rate and fewer shock anomalies in the shock wave region.

The purpose of the current work is to develop a solution method for inCOMPRESSIBLE Navier-Stokes equations, for both velocity and temperature fields, based on artificial compressibility concept. The equations are discretized in Finite-Volume formulation, convective fluxes are calculated using a high-order characteristic-based Roe-like flux splitting method. For time-marching, 5th-order Runge-Kuta algorithm, because of its wide range of stability, is used. The formulation can be used for both steady and unsteady FLOWs. The results for three different flux treatments are presented. The first one is a kind of averaging method and the second and third ones are first and second order methods developed by the authors. The method validation is performed by solving velocity and temperature fields over circular cylinder and ribbed surface, and comparing the results by data in literature which a reasonable agreement would exist. The convergence rate of the method shows a sensible reduction in iteration steps.

Several studies of COMPRESSIBLE FLOWs show that the pressure-strain is the main indicator of the structural compressibility effects. Undoubtedly, this term controls the change in the Reynolds stress anisotropy. Regarding the model of Adumitroiae et al., the slow part of the pressure strain correlation like the Rotta model uses the standard coefficient C1. The model predictions do not show large differences when compressibility increases. Correction of this coefficient using the turbulent Mach number is proposed. The two forms models of Adumitroiae et al. (with and without correction of C1) are considered to study COMPRESSIBLE mixing layers. The obtained results show that the predictions of the proposed compressibility correction model agree with the experiment results of Goebel and Dutton.

In this paper, three new schemes based on normalized variable diagram (NVD) to calculate convection term of conservative equations are developed. The solution technique is of the finite volume type utilizing a co-located arrangement for storage of variables and a uniform mesh. The working variables are velocity and pressure which makes the schemes applicable to both COMPRESSIBLE and in COMPRESSIBLE FLOWs. The interpolation of these schemes has been done with smooth functions and this point improves the convergence and accuracy of the solution. These methods are applied to the computation of steady transonic over bump in channel geometry as well as to the transient shock-tube problem. The results are compared with other computations published in the literature.

In this paper, an explicit finite element based numerical procedure is presented for simulating three-dimensional inviscid COMPRESSIBLE FLOW problems. The implementation of the first-order upwind method and a higher-order artificial dissipation technique on unstructured grids, using tetrahedral elements, is described. Both schemes use a multi-stage Runge-Kutta time-stepping method for time integration. The use of an edge-based data structure in the finite element formulation and its computational merits are also elaborated. Furthermore, the performance of the two schemes in solving a benchmark problem involving transonic FLOW about an ONERA M6 wing is compared and detailed solutions are presented.