F. Dierich¹, P.A. Nikrityuk¹

CMES-Computer Modeling in Engineering & Sciences, Vol.64, No.3, pp. 251-266, 2010, DOI:10.3970/cmes.2010.064.251

Abstract This work presents a numerical investigation of the influence of the roughness of a cylindrical particle on the drag coefficient and the Nusselt number at low Reynolds numbers up to 40. The heated cylindrical particle is placed horizontally in a uniform flow. Immersed boundary method (IBM) with a continuous forcing on a fixed Cartesian grid is used. The governing equations are the Navier Stokes equation and the conservation of energy. A finite-volume based discretization and the SIMPLE algorithm with collocated-variables and Rie-Chow stabilization were used to solve the set of equations. Numerical simulations showed that the impact of the roughness… More >

N. Liu,¹,W. Gao ¹, C.M. Song¹, N. Zhang²

CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.2, pp. 79-102, 2011, DOI:10.3970/cmes.2011.072.079

Abstract This paper presents the probabilistic dynamic analysis of vehicle-bridge interaction systems. The bridge's and vehicle's parameters are considered as random variables as well as the road surface roughness is modeled as random process. A two-degree-of-freedom spring-mass system is used to represent a moving vehicle and the bridge is modeled as an Euler-Bernoulli beam. From the equation of motion for the vehicle-bridge coupling system, the expressions for mean value and standard deviation of bridge response are developed by using the random variable's functional moment method. The effects of the individual system parameters and the road surface roughness on the bridge response… More >

Nikhilkumar D. Abhangi¹, G. M. Deheri¹

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 245-260, 2009, DOI:10.3970/fdmp.2009.005.245

Abstract Efforts have been directed to study and analyze the behavior of a magnetic-fluid-based squeeze film between curved rough circular plates when the curved upper plate (with surface determined by an exponential expression) approaches the stationary curved lower plate (with surface governed by a secant function). A magnetic fluid is used as the lubricant in the presence of an external magnetic field oblique to the radial axis. The bearing surfaces are assumed to be transversely rough and the related roughness is characterized via a stochastic random variable with non-zero mean variance and skewness. The associated Reynolds equation is averaged with respect… More >

Yuhang Jing¹, Ming Hu^2,3

CMC-Computers, Materials & Continua, Vol.38, No.1, pp. 43-59, 2013, DOI:10.3970/cmc.2013.038.043

Abstract Nanostructuring of thermoelectric materials bears promise for manipulating physical parameters to improve the energy conversion efficiency of thermoelectrics. In this paper the thermal transport in Si/Ge superlattice nanotubes is investigated by performing nonequilibrium molecular dynamics simulations aiming at realizing low thermal conductivity by surface roughening. Our calculations revealed that the thermal conductivity of Si/Ge superlattice nanotubes depends nonmonotonically on periodic length and increases as the wall thickness increases. However, the thermal conductivity is not sensitive to the inner diameters due to the strong surface scattering at thin wall thickness. In addition, introducing roughness onto the superlattice nanotubes surface can destroy… More >