R. Ahrem¹, A. Beckert², H. Wendland³

CMES-Computer Modeling in Engineering & Sciences, Vol.12, No.2, pp. 121-136, 2006, DOI:10.3970/cmes.2006.012.121

Abstract We present a new efficient scheme for loose coupling in fluid-structure-interaction problems as they typically appear in the context of aircraft design. This coupling scheme is based upon a multivariate scattered data interpolation approach, based on radial basis functions and partition of unity methods. It allows us to couple arbitrary meshes on fluid and structure side. It conserves virtual work and forces. It is designed for large scale problems and allows the coupling of entire aircraft meshes. More >

Souli, M.¹, Aquelet, N.², Al-Bahkali, E.³, Moatamedi, M.⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.2, pp. 119-133, 2013, DOI:10.3970/cmes.2013.091.119

Abstract To simulate accurately a pressure wave propagation problem, a fine mesh is required in order to capture peak pressures accurately. This may require a very large size problem with several millions of elements. To reduce CPU time and prevent high mesh distortion, a two-dimensional problem for blast ignition and pressure propagation is performed first on a fixed Eulerian mesh. When the pressure wave gets closer to the structure, a three dimensional ALE simulation follows, where the fluid mesh and structure mesh at the fluid structure interface are coincident. The three dimensional problem is performed after mapping history variables from the… More >

Byung-Hyuk Lee¹, Se-min Jeong², Sung-Chul Hwang², Jong-Chun Park³, Moo-Hyun Kim⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.1, pp. 43-63, 2013, DOI:10.3970/cmes.2013.091.043

Abstract The violent free-surface motions interacting with floating vessels containing inner liquid tanks are investigated by using the newly developed Moving Particle Semi-implicit (MPS) method for 2-dimensional incompressible flow simulation. In the present numerical examples, many efficient and robust algorithms have been developed and applied to improve the overall quality and efficiency in solving various highly nonlinear free-surface problems and evaluating impact pressures compared to the original MPS method proposed by Koshizuka and Oka (1996). For illustration, the improved MPS method is applied to the simulation of nonlinear floating-body motions, violent sloshing motions and corresponding impact loads, and vessel motions with… More >

J. Herrmann¹, M. Junge¹, L. Gaul¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.6, pp. 487-504, 2012, DOI:10.3970/cmes.2012.086.487

Abstract The influence of an acoustic field on the dynamic behavior of a flexible structure is a common issue in automotive applications. An example is the pressure-induced structure-borne sound of piping and exhaust systems. Efficient model order reduction and substructuring techniques accelerate the finite element analysis and enable the vibroacoustic optimization of such complex systems with acoustic fluid-structure interaction. This research reviews the application of the Craig-Bampton and the Rubin method to fluid-structure coupled systems and presents two automotive applications. First, a fluid-filled piping system is assembled by substructures or superelements according to the Craig-Bampton method. Fluid and structural partitions are… More >

Souli, M.¹, Gabrys, J.²

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.2, pp. 177-192, 2012, DOI:10.3970/cmes.2012.085.177

Abstract Bird impacts on aircraft are very common and cause significant safety threats to commercial and military aircraft. According to FAA ( Federal American Aviation) regulations, aircraft should be able to land safely following specified types of bird impact on components such as radomes, windshields, engines leading edge structures and other exposed components. Thus exposed components are required to be certified for bird impact. In order to evaluate whether the aircraft is compliant to FAA requirements, several experimental tests and numerical simulations of bird impact on components need to be preformed. This paper presents an experimental and numerical investigation of bird… More >

M.G. Armentano¹, C. Padra², R. Rodríguez³, M. Scheble²

CMES-Computer Modeling in Engineering & Sciences, Vol.84, No.4, pp. 359-382, 2012, DOI:10.3970/cmes.2012.084.359

Abstract In this paper we propose an hp finite element method to solve a two-dimensional fluid-structure vibration problem. This problem arises from the computation of the vibration modes of a bundle of parallel tubes immersed in an incompressible fluid. We use a residual-type a posteriori error indicator to guide an hp adaptive algorithm. Since the tubes are allowed to be different, the weak formulation is a non-standard generalized eigenvalue problem. This feature is inherited by the algebraic system obtained by the discretization process. We introduce an algebraic technique to solve this particular spectral problem. We report several numerical tests which allow… More >

D. Ngo-Cong, N. Mai-Duy, W. Karunasena, T. Tran-Cong

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.5, pp. 459-498, 2012, DOI:10.3970/cmes.2012.083.459

Abstract The partition of unity method is employed to incorporate the moving least square (MLS) and one dimensional-integrated radial basis function (1D-IRBFN) techniques in a new approach, namely local MLS-1D-IRBFN or LMLS-1D-IRBFN. This approach leads to sparse system matrices and offers a high level of accuracy as in the case of 1D-IRBFN method. A new numerical procedure based on the 1D-IRBFN method and LMLS-1D-IRBFN approach is presented for a solution of fluid-structure interaction (FSI) problems. A combination of Chorin's method and pseudo-time subiterative technique is presented for a transient solution of 2-D incompressible viscous Navier-Stokes equations in terms of primitive variables.… More >

K.S. Kim¹, B.H. Lee², M.H. Kim¹, J.C. Park³

CMES-Computer Modeling in Engineering & Sciences, Vol.79, No.3&4, pp. 201-222, 2011, DOI:10.3970/cmes.2011.079.201

Abstract The coupling and interactions between vessel motion and inner-tank sloshing are investigated by a potential-CFD (Computational Fluid Dynamics) hybrid method in time domain. Potential-theory-based 3D diffraction/radiation panel program is used to obtain the hydrodynamic coefficients and wave forces for the simulation of vessel motion in time domain. The liquid sloshing in tanks is simulated in time domain by using the improved Moving Particle Simulation (PNU-MPS) method and it is validated through comparison against sloshing experiments. The calculated sloshing tank forces and moments are applied to the vessel-motion simulation as excitation forces and moments. The updated ship motion, which is influenced… More >

M.Souli¹, F.Erchiqui²

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.3&4, pp. 183-200, 2011, DOI:10.3970/cmes.2011.077.183

Abstract During the design process of membrane structure to resist to high pressure loading, and the characterization of hyperelastic material, a structure made up of thin rubber undergoes large deformation and rotation under high pressure loading out of high pressurized gas. Until recently, to simulate the inflation of the hyperelastic membrane, a uniform pressure based on thermodynamic model or experimental tests is applied to the structure, as boundary conditions. From a computational time point of view, this approach is very fast, since no computational fluid dynamics is involved in the simulation. However, at the late stage of the membrane inflation, uniform… More >

W. A. El-Askary¹

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.3&4, pp. 203-232, 2011, DOI:10.3970/cmes.2011.074.203

Abstract Large eddy simulation (LES) is a viable and powerful tool to analyze unsteady three- dimensional turbulent flows. In this paper, the method of LES is used to compute a plane turbulent supersonic boundary layer subjected to different pressure gradients. The pressure gradients are generated by allowing the flow to pass in the vicinity of an expansion-compression ramp (inclined backward-facing step with leeward-face angle of 25 degrees) for an upstream Mach number of 2.9. The inflow boundary condition is the main problem for all turbulent wall-bounded flows. An approach to solve this problem is to extract instantaneous velocities, temperature and density… More >