Shihong Xiao^1,2,*, Shichao Zhou^1,*, Linlin Yue¹, Xianyou He¹, Maolin Xiang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2549-2567, 2023, DOI:10.32604/fdmp.2023.025063

Abstract In this study, the pressure compensation mechanism of a reducer bellows is analyzed. This device is typically used to reduce the size of undersea instruments and improve related pressure resistance and sealing capabilities. Here, its axial stiffness is studied through a multi-fold approach based on theory, simulations and experiments. The results indicate that the mechanical strength of the reducer bellows, together with the oil volume and temperature are the main factors influencing its performances. In particular, the wall thickness, wave number, middle distance, and wave height are the most influential parameters. For a certain type of reducer bellows, the compensation… More >

Huilong Ren¹, Xiaoying Zhuang^2,3,*, Timon Rabczuk¹

CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.2, pp. 353-383, 2019, DOI:10.32604/cmes.2019.05146

Abstract A dual-support smoothed particle hydrodynamics (DS-SPH) that allows variable smoothing lengths while satisfying the conservations of linear momentum, angular momentum and energy is developed. The present DS-SPH is inspired by the dual-support, a concept introduced from dual-horizon peridynamics from the authors and applied here to SPH so that the unbalanced interactions between the particles with different smoothing lengths can be correctly considered and computed. Conventionally, the SPH formulation employs either the influence domain or the support domain. The concept of dual-support identifies that the influence domain and the support domain involves the duality and should be simultaneously in the SPH… More >

François Bouchon^{1, *}, Thierry Dubois¹, Nicolas James²

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 165-184, 2019, DOI:10.32604/cmes.2019.04841

Abstract We present a cut-cell method for the simulation of 2D incompressible flows past obstacles. It consists in using the MAC scheme on cartesian grids and imposing Dirchlet boundary conditions for the velocity field on the boundary of solid structures following the Shortley-Weller formulation. In order to ensure local conservation properties, viscous and convecting terms are discretized in a finite volume way. The scheme is second order implicit in time for the linear part, the linear systems are solved by the use of the capacitance matrix method for non-moving obstacles. Numerical results of flows around an impulsively started circular cylinder are… More >

D. Ishihara¹, T. Horie¹

CMES-Computer Modeling in Engineering & Sciences, Vol.101, No.6, pp. 421-440, 2014, DOI:10.3970/cmes.2014.101.421

Abstract In this study, a projection method for the monolithic interaction system of an incompressible fluid and a structure using a new algebraic splitting is proposed. The proposed method splits the monolithic equation system into the equilibrium equations and the pressure Poisson equation (PPE) algebraically using the intermediate velocity in the nonlinear iterations. Since the proposed equilibrium equation satisfies the interface condition, the proposed method is strongly coupled. Moreover, the proposed PPE enforces the incompressibility constraint. Different from previous studies, the proposed algebraic splitting never generates any Schur complement. The proposed method is applied to a channel with a flexible flap,… More >

M. Chatterjee, A.K. Mahendra, A.Sanyal, G. Gouthaman

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.4, pp. 385-402, 2012, DOI:10.3970/cmes.2012.083.385

Abstract In this paper, we describe an Incompressible Navier-Stokes (INS) sol -ver using mesh less least square based discretisation on arbitrary distribution of points. The method uses modified Artificial Compressibility Method (ACM) with least square based discretisation. The Solver operates on an arbitrary distribution of points and uses a novel least squares based method that replaces the normal equations approach. This method generates the non-symmetric cross-product matrix by suitable selection of sub stencils such that the matrix is diagonally dominant and well conditioned. The INS solver has been validated with results available in literature for standard test cases. More >

G. Venkata Ramana Reddy^1,*, Y. Hari Krishna¹

FDMP-Fluid Dynamics & Materials Processing, Vol.14, No.3, pp. 213-222, 2018, DOI: 10.3970/fdmp.2018.00411

Abstract The objective of the present problem is to investigate a two-dimensional unsteady flow of a viscous incompressible electrically conducting fluid over a stretching surface taking into account a transverse magnetic field of constant strength. Applying the similarity transformation, the governing boundary layer equations of the problem converted into nonlinear ordinary differential equations and then solved numerically using fourth order Runge-Kutta method with shooting technique. The effects of various parameters on the velocity and temperature fields as well as the skin-friction coefficient and Nusselt number are presented graphically and discussed qualitatively. More >

M.H. Djavareshkian¹

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.4, pp. 329-342, 2005, DOI:10.3970/fdmp.2005.001.329

Abstract A pressure-based Euler scheme, based on a collocated grid arrangement is described. The newly developed algorithm has two new prominent features: (i) the use of normalized variables to bound the convective fluxes and (ii) the use of a high-resolution scheme in calculating interface density values to enhance the shock-capturing property of the algorithm. The algorithm is first tested for flows at different Mach numbers ranging from subsonic to supersonic on a bump in a channel geometry; then the results are compared with the corresponding ones obtained without the bounded scheme in the correction step. The output is also compared with… More >