A. Baradaran Rahimi
Mechanical Engineering, Ferdowsi University of Mashhad
[ 1 ] - Estimation of the Strength of the Time-dependent Heat Source using Temperature Distribution at a Point in a Three Layer System
In this paper, the conjugate gradient method coupled with adjoint problem is used in order to solve the inverse heat conduction problem and estimation of the strength of the time- dependent heat source using the temperature distribution at a point in a three layer system. Also, the effect of noisy data on final solution is studied. The numerical solution of the governing equations is obtained b...
[ 2 ] - Comparison of Lift and Drag Forces for Some Conical Bodies in Supersonic Flow Using Perturbation Techniques
Numerical methods are not always convergent especially in higher velocities when shock waves are involved. A comparison analysis is performed to study the supersonic flow over conical bodies of three different cross sections circular, elliptic and squircle (square with rounded corners) shaped using Perturbation techniques to find flow variables analytically. In order to find lift and drag forc...
[ 3 ] - NUMERICAL MODELING OF CHARRING MATERIAL ABLATION WITH CONSIDERING CHEMICAL REACTION, MASS TRANSFER AND SURFACE HEAT TRANSFER EFFECTS
Presently there is a little information that relates to heat shield systems. Also this information is not certain in so many cases. The main reason is that accurate calculations for measuring the sacrificing rate of various materials have not been obtained yet. Additionally, the real scale test has two disadvantages: high cost and low flexibility, and for each case we must perform a new test...
[ 4 ] - A Numerical Study of Flow and Heat Transfer Between Two Rotating Vertically Eccentric Spheres with Time- Dependent Angular Velocities
The transient motion and the heat transfer of a viscous incompressible flow contained between two vertically eccentric spheres maintained at different temperatures and rotating about a common axis with different angular velocities is numerically considered when the angular velocities are an arbitrary functions of time. The resulting flow pattern, temperature distribution, and heat transfer char...
[ 5 ] - Axi-symmetric Stagnation–Point Flow and Heat Transfer Obliquely Impinging on a Rotating Circular Cylinder
Laminar stagnation flow, axi-symmetrically yet obliquely impinging on a rotating circular cylinder, as well as its heat transfer is formulated as an exact solution of the Navier-Stokes equations. Rotational velocity of the cylinder is time-dependent while the surface transpiration is uniform and steady. The impinging stream is composed of a rotational axial flow superposed onto irrotational rad...
[ 6 ] - Unsteady Free Convection from a Sphere in a Porous Medium with Variable Surface Temperature
In this paper a transient free convection flow around a sphere with variable surface temperature and embedded in a porous medium has been considered. The temperature of the sphere is suddenly raised and subsequently maintained at values that varies with position on surface. The method of asymptotic expansions is applied for small Rayleigh numbers and then a finite-difference scheme is used to s...
[ 7 ] - A New Approach in Preliminary Design of Closed Loop Solar Thermal Systems (RESEARCH NOTE)
In this paper, a model for closed loop solar system is presented and an attempt is made to generalize the model to be utilized for primary design of any solar active thermal system. This model may be used for systems in which gas or a liquid are fluids that flow. Two new parameters, namely, the system heat delivery factor and the system heat absorption factor are introduced in the model. These ...
[ 8 ] - Transient Natural Convection Flow on an Isothermal Vertical Wall at High Prandtl Numbers: Second-Order Approximation
The method of matched asymptotic expansions, which has been used in previous studies of steady natural convection flow, is extended here to transient natural convection flow at high Prandtl number (Pr). Second-order expansion solutions, valid for large Prandtl numbers, are presented for the transient natural convection flow near a vertical surface which undergoes a step change in temperature. T...
[ 9 ] - Analytic Solution for Hypersonic Flow Past a Slender Elliptic Cone Using Second-Order Perturbation Approximations
An approximate analytical solution is obtained for hypersonic flow past a slender elliptic cone using second-order perturbation techniques in spherical coordinate systems. The analysis is based on perturbations of hypersonic flow past a circular cone aligned with the free stream, the perturbations stemming from the small cross-section eccentricity. By means of hypersonic approximations for the ...
[ 10 ] - Pressure Calculation in the Flow Between Two Rotating Eccentric Cylinders at High Renolds Numbers
This paper reports the result of an analytical investigation of a steady, incompressible and viscous flow between two eccentric, rotating cylinders at high Reynolds number. A one dimensional case is far from reality because the gap between the cylinders is very small. Further, when their axes are displaced by a small distance, usually caused by bearing loads, two dimensional effects become obvi...
[ 11 ] - Freezing in a Finite Slab Using Extensive Perturbation Expansions Method
In this paper Mathematica is used to solve the moving boundary problem of freezing in a finite slab for higher order perturbations. Mathematica is a new system which makes it possible to do algebra with computer. More specifically, it enables researchers to find the location of the ice at any time for as high order of perturbation as one whishes. Using of Mathematica and outer solution and an i...
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