ELECTROHYDRODYNAMIC THERMAL INSTABILITY IN A WALTERS’ (MODEL B') ROTATING NANOFLUID SATURATING A POROUS MEDIUM
The onset of thermal instability in a dielectric rotating nanofluid layer saturating a porous medium with vertical AC electric field is investigated by employing Darcy model for porous medium. The rheology of the nanofluid is described by Walters’ (model B’) for calculating the shear stresses from the velocity gradients. The employed mo...
By Gian C. Rana, Poonam Gautam, Hemlata Saxena
1D and 3D Modeling of Modern Automotive Exhaust Manifold
This paper presents the simulation of the multi-cylinder 4-stroke cycle spark-ignition engine using a commercial simulation tool, AVL BOOST and Fire. Various models were examined to select the appropriate models that would best serve to analyze the main components of the exhaust systems: the plenum chamber, the muffler and the exhaust manifold bran...
By Barhm Mohamad, Andrei Zelentsov
A Proposed Method for Determining Propulsion Coefficient Based on Testing Motor Freighters on Danube Waterway Network
The paper presents a proposal of mathematical models for the determination of propulsion coefficient, ηpp, intended for the analysis of motor freighters applied on the river watercourses. As the main paper contribution three different model types are developed, depending on the variable which contributes to ηpp value. These variables are: 1...
By Radoslav Rajkovic, Dragan Mitic, Aleksandar Lebl, Snežana Rajkovic
MODELING OF DAMAGED CONCRETE USING INITIAL DEGRADATION PARAMETER
A stress-strain history in the material of real concrete structures is usually unknown. An effect of concrete degradation is analyzed to describe how the initial degradation parameter can describe the stress-strain history. The idea is to introduce the initial damage of the structure by the degradation parameter to calculate the internal variables ...
By Dragan Rakić, Vladimir Dunić, Miroslav Živković, Nenad Grujović, Dejan Divac
NUMERICAL STUDY ON HEAT TRANSFER IN MULTILAYERED STRUCTURES OF MAIN GEOMETRIC FORMS MADE OF DIFFERENT MATERIALS
The article proposed a general research scheme of heat transfer process in multilayer constructions for three basic geometric forms in order to simulate fire distribution. The scheme is based on linear differential equations, the Fourier method and the modified method of Eigen functions. The work considers five different layers’ design and do...
By Roman M. Tatsiy, Oleg Yu Pazen, Sergiy Ya. Vovk, Lubomyr Ya. Ropyak, Tetiana O. Pryhorovska
OSCILLATIONS OF MULTILAYER VISCOELASTIC COMPOSITE TOROIDAL PIPES
This article discusses a method for calculating the dynamic characteristics of thin-walled viscoelastic composite pipes made by continuous winding under the influence of internal hydrodynamic pressures. The solution is based on an approximate energy method based on the instant theory of shells and the second-order Lagrange equation. Initial technol...
By Muhsin Kh. Muhsin Kh., Ismail I. Safarov, Mirziyod Mirsaidov
VISCOSITY VARIATION EFFECT ON THE MAGNETIC FLUID LUBRICATION OF A SHORT BEARING
The performance of a magnetic fluid based short bearing is examined with the effect of viscosity variation. The pressure temperature relation of Tipei (1962) concerning viscosity variation is adopted here. The Neuringer-Rosensweig’s model has been considered for the magnetic fluid flow. The related modified Reynolds type equation is solved fo...
By Jimit R. Patel, Gunamani Deheri
TURBULENT FLOW CONTROL WITH VORTEX GENERATORS AROUND A SYMMETRICAL AIRFOIL AT HIGH ATTACK ANGLES
The flow on the upper surface of NACA 0015 airfoil is subject to an adverse pressure gradient when the incidence increases. This leads to the boundary layer separation which causes losses in the aerodynamic performances. Control using Vortex Generators (VGs) is a simple passive mean used to delay or eliminate the flow separation from the wall. The ...
By Hocine Tebbiche, Mohammed Saîd Boutoudj
The Effects of Buoyancy Force on the Irreversibility of Three-Dimensional Step Flow in an Inclined Duct
This research deals with the study of the irreversibility of three-dimensional mixed convection flow in an inclined duct with step. To reach this goal, an analysis of entropy generation is carried out according to the second law of thermodynamics. The effects of buoyancy force on the flow irreversibility are analyzed with all details. The results s...
By Meysam Atashafrooz, Tahereh Asadi
EFFECT OF NONLINEAR RADIATIVE HEAT AND MASS TRANSFER ON MHD FLOW OVER A STRETCHING SURFACE WITH VARIABLE CONDUCTIVITY AND VISCOSITY
A theoretical investigation on the flow of nonlinear magnetohydrodynamic (MHD), laminar, viscous, incompressible boundary layer fluid with thermal radiative heat transfer and variable properties past a stretching plate was carried out. The liquid is taken to be gray, absorbing, emitting but with non-scattering medium. The main nonlinear equations g...
By Akindele M. Okedoye, Sulyman O. Salawu