Jinsheng Wang¹, Liqing Liu², Yiming Chen², Lechun Liu², Dayan Liu³

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.1, pp. 69-85, 2015, DOI:10.3970/cmes.2015.104.069

Abstract The aim of this paper is to seek the numerical solution of a class of variable order fractional integral-differential equation in terms of Bernstein polynomials. The fractional derivative is described in the Caputo sense. Four kinds of operational matrixes of Bernstein polynomials are introduced and are utilized to reduce the initial equation to the solution of algebraic equations after dispersing the variable. By solving the algebraic equations, the numerical solutions are acquired. The method in general is easy to implement and yields good results. Numerical examples are provided to demonstrate the validity and applicability of More >

F.Z. Chen^1,2, H.F. Qiang¹, W.R. Gao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.1, pp. 41-68, 2015, DOI:10.3970/cmes.2015.104.041

Abstract A coupled method describing gas-solid two-phase flow has been proposed to numerically study the bubble formation at a single orifice in gas-fluidized beds. Solid particles are traced with smoothed particle hydrodynamics, whereas gas phase is discretized by finite volume method. Drag force, gas pressure gradient, and volume fraction are used to couple the two methods. The effect of injection velocities, particle sizes, and particle densities on bubble growth is analyzed using the coupled method. The simulation results, obtained for two-dimensional geometries, include the shape and diameter size of a bubble as a function of time; More >

Chein-Shan Liu¹, Satya N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.1, pp. 1-39, 2015, DOI:10.3970/cmes.2015.104.001

Abstract A double optimal solution of an n-dimensional system of linear equations Ax = b has been derived in an affine m « n. We further develop a double optimal iterative algorithm (DOIA), with the descent direction z being solved from the residual equation Az = r₀ by using its double optimal solution, to solve ill-posed linear problem under large noise. The DOIA is proven to be absolutely convergent step-by-step with the square residual error ||r||² = ||b - Ax||² being reduced by a positive quantity ||Az_k||² at each iteration step, which is found to be better than those algorithms based More >

N. Laaroussi^1*, Y. Chihab¹, M. Garoum¹, L-V. Bénet², F. Lacroux³

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.4, pp. 354-365, 2015, DOI:10.3970/fdmp.2015.011.354

Abstract This study is based on the modeling of the air flow in the hall building including heating and air-conditioning systems. The building contains two converter stations “valves” considered as heat sources. Heat transfer in the hall is numerically simulated using the standard k-ε model of turbulence. For a very hot weather, this study aims to evaluate the local temperatures in the ambient air of the hall, with assuming running valves and air conditioning device in open loop with a 35°C inlet temperature. The study has shown that the air conditioning is efficient enough to maintain More >

SouadMorsli^1,*, Amina Sabeur¹, Mohammed El Ganaoui²

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.4, pp. 342-353, 2015, DOI:10.3970/fdmp.2015.011.342

Abstract The aim of this work is the numerical simulation of the combustion of hydrogen with air in a burner and the numerical solution of local entropy generation rate in the combustion chamber. The effects of equivalence ratio φ and oxygen percentage γ on combustion and entropy generation rates are studied for different φ(ranging from 0 to 1.0) and γ values (ranging from 10 to 30%). The predictions show that the increase of φ (or the decrease of λ ) reduces notably the reaction rate levels. The equations of continuity, of energy and momentum are solved by More >

R. Savino¹, M . Visone², D. Rossetto³, V. D'Oriano⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.4, pp. 331-341, 2015, DOI:10.3970/fdmp.2015.011.331

Abstract This paper presents two applications of Computational Fluid Dynamics (CFD) to super and mega yacht design, based on the Volume of Fluid method. After an overview of recent literature on the subject, the analysis of the hydrodynamic performances of different hull configurations and of different appendage configurations is presented. More >

P. Pasolini^1,2, R. Savino¹, F. Franco¹, S. De Rosa¹

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 301-324, 2015, DOI:10.3970/fdmp.2015.011.301

Abstract The aim of the present work is to provide a first attempt to set an aero-thermo-elastic methodology for deployable atmospheric re-entry decelerators operating at high Mach number and high dynamic pressure. Because of the severity of re-entry conditions such as high temperatures, high pressures and high velocities, the behavior of their flexible structures is a hard target to assess. In this paper a partitioned Fluid Structure Interaction (FSI) approach based on the integration of different commercial software (STAR-CCM+ and ABAQUS) is presented. In order to validate the specific codes and the overall strategy for structural More >

Abd el malik Bouchoucha^1,2, Rachid Bessaïh¹

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 279-300, 2015, DOI:10.3970/fdmp.2015.011.279

Abstract The present paper deals with a numerical study of natural convection in a square cavity filled with a nanofluid. The left and right vertical walls of the cavity are maintained at a local temperature T_h (heat source) and a local cold temperature T_C, respectively. Horizontal walls are assumed to be adiabatic. The governing equations are discretized by using the finite volume method and solved by the SIMPLER algorithm. Our computer fortran code is validated through comparison with numerical results found in the literature. Results are presented in terms of streamlines, isotherms, local and average Nusselt numbers More >

G. Frulla¹, P. Gili¹, M. Visone², V. D’Oriano^2,3, M. Lappa⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 257-277, 2015, DOI:10.3970/fdmp.2015.011.257

Abstract A practical engineering approach to the design of a 60 kW wind generator with improved performances is presented. The proposed approach relies on the use of a specific, "ad hoc'' developed software, OPTIWR (Optimization Software), expressly conceived to define an "optimum'' rotor configuration in the framework of the blade-element-momentum theory. Starting from an initial input geometric configuration (corresponding to an already existing 50 kW turbine) and for given values of the wind velocity V_wind and of the advance ratio X = V_wind/ΩR (where Ω is the blade rotational speed and R is the propeller radius), this software… More >

V. N. Lad¹, Z. V. P. Murthy^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 241-255, 2015, DOI:10.3970/fdmp.2015.011.241

Abstract Free liquid jets are of great technical importance in a variety of applications like ink-jet printing, glass painting, spray coating and metal cutting. Here we consider the changes induced in the dynamics of such jets by the presence of obstructions at the tube exit. Using stainless steel bars of 1.5 mm diameter as obstruction objects and aqueous solutions of glycerol of varying concentrations as working fluids, we performed experiments for different configurations, including a single rod at the centre of the tube exit, two parallel rods equidistant from the centre of the tube, and a… More >