Dr. V. Ramani Bai, Prof. Mohamad Rom Tamjis

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.1, pp. 31-40, 2007, DOI:10.3970/icces.2007.004.031

Abstract The aim of this paper is to develop a fuzzy logic model for deriving optimal operational rules at the macro level for better performance and control of hydro-power generation. System modeling based on conventional mathematical tools is not well suited for dealing with ill-defined and uncertain systems. By contrast, a fuzzy inference system employing "if-then" rules can model the qualitative aspects of human knowledge and reasoning processes without employing precise quantitative analyses. In fuzzy logic, diagnosis is based on imprecise data. For instance, when the demand is `very high' i.e. in linguistic term, then its value is important in assisting… More >

J. Kato¹, K. Inaba², M. Yamamoto³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.1, pp. 25-30, 2007, DOI:10.3970/icces.2007.004.025

Abstract Pulse detonation turbine engines (PDTEs), which are used as power generation, are desirable to use hydrocarbon from the aspect of infrastructure of fuels. In the present study, we investigate the performance of PDEs using mixed hydrocarbon fuels. With the detailed 42-species and 168-step mechanism, numerical simulations on mixed-fuel-and-air PDEs are conducted. We use CH4-C3H8, CH4-H2, and C3H8-H2 as fuels, and examine characteristic features of detonations with different blend ratios. We perform calculations on the Chapman-Jouguet detonation speeds and chemical reaction lengths, and investigate ZND profiles of chemical reactions. Then we evaluate PDEs performances by changing blend ratios. These results show… More >

Shigeaki Shiotani¹, Atsushi Hagiwara², Yoshitaka Sakakura³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.1, pp. 19-24, 2007, DOI:10.3970/icces.2007.004.019

Abstract Marine fish larvae are fragile against physical stress. However, few studies have been conducted to evaluate the flow field in a rearing tank, which is assumed to provide a high degree of physical stress to marine fish larvae. This paper is a report on the numerical estimation of stationary flow in the rearing tank of marine fish larvae. The calculated flow in the rearing tank was compared with the experimental one. The calculation of the stationary flow in the rearing tank showed good qualitative and quantitative agreement with the experimental results. More >

Kazuhiko Kakuda¹, Tomohiro Aiso¹, Shinichiro Miura²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.1, pp. 11-18, 2007, DOI:10.3970/icces.2007.004.011

Abstract The applications of a finite element scheme to three-dimensional incompressible viscous fluid flows are presented. The scheme is based on the Petrov-Galerkin weak formulation with exponential weighting functions. The incompressible Navier-Stokes equations are numerically integrated in time by using a fractional step strategy with second-order accurate Adams-Bashforth scheme for both advection and diffusion terms. Numerical solutions for flow around a circular cylinder and flow around a railway vehicle in a tunnel are presented. More >

S. Sriram¹, S. Pushpavanam¹, Abhijit P. Deshp,e¹, E.G. Tulapurkara²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.1, pp. 1-10, 2007, DOI:10.3970/icces.2007.004.001

Abstract The flow in a periodically-driven cavity is studied experimentally using Particle Image Velocimetry (PIV) and the results are compared with Computational Fluid Dynamics (CFD) simulations. The experiments are carried out in a cuboid of 0.1x 0.1m x 0.02 m size with glycerol as the fluid. Measurements are carried out at various amplitudes and frequencies of lid motion. The planar velocity measurements are made at three different z-planes and x-planes. It is found that the temporal variations of x-, y- and z-components of velocities of the flow are periodic, with the imposed plate frequency as the dominant frequency. Computation using FLUENT… More >

Zhenquan Li¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.4, pp. 251-256, 2007, DOI:10.3970/icces.2007.003.251

Abstract An adaptive three-dimensional mesh refinement method based on the law of mass conservation has been introduced and tested using some analytical velocity fields as accurate in identifying singular point, asymptotic plane and drawing closed streamlines. This paper further investigates the adaptive mesh refinement method using a velocity field that is due to a uniform strain and a point vortex. Similar results have been obtained. More >

Ye.Ye. Deryugin¹, G.V. Lasko^2,1, S. Schmauder²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.4, pp. 243-250, 2007, DOI:10.3970/icces.2007.003.243

Abstract The results of 2D simulation of strain localizations on the meso-level in the surface layer of a polycrystal with a highly pronounced Portevin Le Chatelier (PLC) effect are presented. For such a purpose the Relaxation Element Method (REM) has been used. A fundamental property of solid "plastic deformation is accompanied by stress relaxation in local volumes of a loaded solid" lies on the basis of this method. The elaborated REM model operates on the principle of cellular automata. The results are in good qualitative agreement with known experimental data. More >

V. Romero¹, S. Kanaun²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.4, pp. 233-242, 2007, DOI:10.3970/icces.2007.003.233

Abstract In this work Gaussian approximating functions proposed in the works of V. Maz'ya are used for the solution of the integral equations of elasto-plasticity for isotropic bodies. The use of this functions esentially simplify the calculation of the elements of the final matrix of the linear algebraic equations of the discretized problem. The elements of this matrix turn to be a combination of simple elementary functions. The method is applied to a 2D rectangular body that has a cut on a border and is subjected to axial tension. The convergence of the method is studied on this example. More >

Hans Mühlhaus¹, Laurent Bourgouin¹, Alina Hale¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.4, pp. 225-232, 2007, DOI:10.3970/icces.2007.003.225

Abstract We use a finite element formulation of the level set method to model the evolution of the free surface of axi-symmetric spreading flows of highly viscous media on a horizontal plane. We consider specifically the growth of a lava dome as an example however similar problems also occur in flows involving the spreading of molten metals or ceramics. Here we restrict ourselves on constant viscosity fluids for simplicity. In real lavas or melts the viscosity is highly temperature dependent. This manifests itself in the formation of thin predominantly elastic-plastic boundary layers along the free (cold) surfaces of the spreading flows.… More >

S. Tanaka¹, H. Okada¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.4, pp. 217-224, 2007, DOI:10.3970/icces.2007.003.217

Abstract It has been recognized that the bottle-neck in solid/structural analyses using the finite element method is in their model generation phase. Methodologies that eliminate the needs for "elements" have been proposed by many researchers. They can be categorized into "meshless" and "virtually meshless" finite element methods. The "meshless" method may be represented by moving least square Ptrov-Galerkin (MLPG) method [1] and element free Galerkin Method (EFGM) [2]. The free-mesh method [3] and voxel finite element method [4], etc. are classified to be the "virtually meshless" approaches. The "meshless" methods eliminated needs for element connectivity information in their input data and… More >