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.

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.

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).

In the present study, the onset of double diffusive reaction-convection in a FLUID layer with VISCOUS FLUID, heated and salted from below subject to chemical equilibrium on the boundaries, has been investigated. Linear and nonlinear stability analysis have been performed. For linear analysis normal mode technique is used and for nonlinear analysis minimal representation of truncated Fourier series is used. The effect of Lewis number, solute Rayleigh number, reaction rate and Prandtl number on the stability of the system is investigated. A weak nonlinear theory based on the truncated representation of Fourier series method is used to find the heat and mass transfer.

In the present study, nonlinear vibration of coupled carbon nanotubes (CNTs) in presence of surface effect is investigated based on nonlocal Euler-Bernoulli beam (EBB) theory. CNTs are embedded in a visco-elastic medium and placed in the uniform longitudinal magnetic field. Using von Karman geometric nonlinearity and Hamilton’s principle, the nonlinear higher order governing equations are derived. The differential quadrature (DQ) method is applied to obtain the nonlocal frequency of coupled visco-CNTs system. The effects of various parameters such as the longitudinal magnetic field, visco-Pasternak foundation, Knudsen number, surface effect, aspect ratio and velocity of conveying VISCOUS are specified. It is shown that the longitudinal magnetic field is responsible for an up shift in the frequency and an improvement of the instability of coupled system. Results also reveal that the surface effect and internal conveying FLUID plays an important role in the instability of nano coupled system. Also, it is found that trend of figures have good agreement with previous researches. It is hoped that the nonlinear results of this work could be used in design and manufacturing of nano/micro mechanical system in advanced nanomechanics applications where in this study the magnetic field is a controller parameter.

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 system consisting of two rigid bodies in a VISCOUS FLUID is considered. The main body with mass M is placed in a VISCOUS inCOMPRESSIBLE FLUID, and the body with mass m moves inside the main body. This system is known as vibrobot which can be used in arbitrary inspection FLUID mechanic objects such as oil industries pipes and tanks, as well as marine industries, medicine, etc. In this paper, the interaction between the vibrobot and VISCOUS FLUID is studied to achieve the motion laws of the vibrobot with the harmonic oscillation of internal mass. Also the flow structure around vibrobot and its effects on the hydrodynamic force acting on the vibrobot are investigated. Analyses are carried out by direct numerical simulation of the vibrobot motion in a VISCOUS FLUID by OpenFOAM package. Calculations are performed for the following combinations of control parameters; The ratio of the VISCOUS FLUID mass to the vibrobot mass m_1=0.35, the ratio of the internal mass to the vibrobot mass m_2=0.325 and dimensionless oscillation frequency f=1.5, when Reynolds number takes values in the range of 50<Re<250. Calculations have been performed with different initial approximations, determined by different initial velocities of the incident flow.