Open Access
ARTICLE
Kuntao Ye1,*, Yan Luo1, Yingtao Jiang2,*
CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 261-276, 2018, DOI:10.3970/cmes.2018.114.261
Abstract Torsional micromirror devices have been widely used in micro displays, RF switches, optical communications, and optical coherence tomography systems. In order to study the stability of electrostatically driven torsional micromirror system with double bottom plates and two voltage sources, a dimensionless, two degrees of freedom (2-DoF) dynamic model was constructed. Governed by the dimensionless phase space model equation, the pull-in and bifurcation phenomena were analyzed using the Hamiltonian method and numerical simulation. In particular, the influence of the damping coefficient and the torsion-bending coupling effect on the phase trajectory was investigated. Furthermore, the conditions that can lead to pull-in were… More >
Open Access
ARTICLE
Haijian Shao1, 2, Xing Deng1, 2, *
CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 277-293, 2018, DOI:10.3970/cmes.2018.114.277
Abstract High accurary in wind speed forcasting remains hard to achieve due to wind’s random distribution nature and its seasonal characteristics. Randomness, intermittent and nonstationary usually cause the portion problem of the wind speed forecasting. Seasonal characteristics of wind speed means that its feature distribution is inconsistent. This typically results that the persistence of excitation for modeling can not be guaranteed, and may severely reduce the possibilities of high precise forecasting model. In this paper, we proposed two effective solutions to solve the problems caused by the randomness and seasonal characteristics of the wind speed. (1) Wavelet analysis is used to… More >
Open Access
ARTICLE
Sanjay K. Sharma1, V. R. Kalamkar1, *
CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 295-319, 2018, DOI:10.3970/cmes.2018.114.295
Abstract The three-dimensional numerical investigation of an incompressible flow through rib roughened solar air heater is carried out. A combination of thin transverse and truncated ribs is attached on the absorber plate to study its effect on the heat transfer and friction factor. The parameters in the form of Reynolds number (Re) of 4000-16000, relative roughness pitch (P/e) of 8-18 and relative roughness height (e/Dh) of 0.0366-0.055 is considered for the analysis. The CFD code ANSYS FLUENT is used to solve the governing equations of turbulent flow. The RNG k–ε turbulence model is used to solve the transport equations with enhanced… More >
Open Access
ARTICLE
V. Venkatachalam1, *, D. Prabhakaran1
CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 321-334, 2018, DOI:10.3970/cmes.2018.114.321
Abstract This paper presents, using Lyapunov-Krasovskii functional technique combined with reciprocal convex lemma is considered for a networked control temperature control system with additive time-varying-delays. In the stability analysis, a new LK functional is assumed, and take the time-derivative of the (LK) functional, using reciprocal convex combination technique was employed to obtain less conservative stability criteria. Finally, the proposed stability analysis culminates into a stability criterion in the LMI (linear matrix inequalities) framework. The results obtained are in accordance with the theoretically obtained in the temperature control system and they are closer to the standard benchmark temperature-control system. More >
Open Access
ARTICLE
Shenghu Ding1,*, Qingnan Liu1
CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 335-349, 2018, DOI:10.3970/cmes.2018.114.335
Abstract A multi-layered model for heat conduction analysis of a thermoelectric material strip (TEMs) with a Griffith crack under the electric flux and energy flux load has been developed. The materials parameters of the TEMs vary continuously in an arbitrary manner. To derive the solution, the TEMs is divided into several sub-layers with different material properties. The mixed boundary problem is reduced to a system of singular integral equations, which are solved numerically. The effect of strip width on the electric flux intensity factor and thermal flux intensity factor are studied. More >
Open Access
ARTICLE
Cheinshan Liu1,2, Fajie Wang1,3,*, Wenzheng Qu4,*
CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 351-380, 2018, DOI:10.3970/cmes.2018.114.351
Abstract In this paper we propose a novel two-stage method to solve the three-dimensional Poisson equation in an arbitrary bounded domain enclosed by a smooth boundary. The solution is decomposed into a particular solution and a homogeneous solution. In the first stage a multiple-scale polynomial method (MSPM) is used to approximate the forcing term and then the formula of Tsai et al. [Tsai, Cheng, and Chen (2009)] is used to obtain the corresponding closed-form solution for each polynomial term. Then in the second stage we use a multiple/scale/direction Trefftz method (MSDTM) to find the solution of Laplace equation, of which the… More >