Development of a finite element flow solver for solving three-dimensional incompressible Navier–Stokes solutions on multiple GPU cards

2018 ◽  
Vol 167 ◽  
pp. 285-291 ◽  
Author(s):  
Neo Shih-Chao Kao ◽  
Tony Wen-Hann Sheu
Author(s):  
Juan P. Pontaza ◽  
Raghu G. Menon

The paper describes a fluid-structure interaction (FSI) modeling approach to predict the VIV response of a flexible pipe by coupling a three-dimensional viscous incompressible Navier-Stokes solver with a beam finite element solver – in time domain. The flexible pipe is modeled as an Euler-Bernoulli beam subject to instantaneous flow-induced forces and solved using C1 conforming finite element basis functions in space and an unconditionally stable Newmark-type discretization scheme in time. At each time step the instantaneous incremental displacement is fed back to the fluid flow solver, where the position of the pipe is updated to compute the resulting instantaneous flow field and associated flow-induced forces. Numerical predictions from the FSI model are compared to experimental measurements of a flexible pipe subject to uniform free-stream currents.


2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Juan P. Pontaza ◽  
Raghu G. Menon

This paper describes a fluid-structure interaction (FSI) modeling approach to predict the vortex-induced vibration response of a pipeline span by coupling a three-dimensional viscous incompressible Navier–Stokes solver with a beam finite element solver in time domain. The pipeline span is modeled as an Euler–Bernoulli beam subject to instantaneous flow-induced forces and solved using finite element basis functions in space and an unconditionally stable Newmark-type discretization scheme in time. At each time step, the instantaneous incremental displacement is fed back to the fluid flow solver, where the position of the pipeline is updated to compute the resulting instantaneous flow field and associated flow-induced forces. Numerical predictions from the FSI model are compared to current tank experimental measurements of a pipeline span subject to uniform free-stream currents.


2004 ◽  
Vol 10 (5) ◽  
pp. 373-385
Author(s):  
Steffen Kämmerer ◽  
Jürgen F. Mayer ◽  
Heinz Stetter ◽  
Meinhard Paffrath ◽  
Utz Wever ◽  
...  

This article describes the development of a method for optimization of the geometry of three-dimensional turbine blades within a stage configuration. The method is based on flow simulations and gradient-based optimization techniques. This approach uses the fully parameterized blade geometry as variables for the optimization problem. Physical parameters such as stagger angle, stacking line, and chord length are part of the model. Constraints guarantee the requirements for cooling, casting, and machining of the blades.The fluid physics of the turbomachine and hence the objective function of the optimization problem are calculated by means of a three-dimensional Navier-Stokes solver especially designed for turbomachinery applications. The gradients required for the optimization algorithm are computed by numerically solving the sensitivity equations. Therefore, the explicitly differentiated Navier-Stokes equations are incorporated into the numerical method of the flow solver, enabling the computation of the sensitivity equations with the same numerical scheme as used for the flow field solution.This article introduces the components of the fully automated optimization loop and their interactions. Furthermore, the sensitivity equation method is discussed and several aspects of the implementation into a flow solver are presented. Flow simulations and sensitivity calculations are presented for different test cases and parameters. The validation of the computed sensitivities is performed by means of finite differences.


2019 ◽  
Vol 7 (12) ◽  
pp. 435
Author(s):  
Mohammad Rasidi Rasani ◽  
Hazim Moria ◽  
Michael Beer ◽  
Ahmad Kamal Ariffin

Flow-induced vibrations of a flexible cantilever plate, placed in various positions behind two side-by-side cylinders, were computationally investigated to determine optimal location for wake-excited energy harvesters. In the present study, the cylinders of equal diameter D were fixed at center-to-center gap ratio of T / D = 1 . 7 and immersed in sub-critical flow of Reynold number R e D = 10 , 000 . A three-dimensional Navier–Stokes flow solver in an Arbitrary Lagrangian–Eulerian (ALE) description was closely coupled to a non-linear finite element structural solver that was used to model the dynamics of a composite piezoelectric plate. The cantilever plate was fixed at several positions between 0 . 5 < x / D < 1 . 5 and - 0 . 85 < y / D < 0 . 85 measured from the center gap between cylinders, and their flow-induced oscillations were compiled and analyzed. The results indicate that flexible plates located at the centerline between the cylinder pairs experience the lowest mean amplitude of oscillation. Maximum overall amplitude in oscillation is predicted when flexible plates are located in the intermediate off-center region downstream of both cylinders. Present findings indicate potential to further maximize wake-induced energy harvesting plates by exploiting their favorable positioning in the wake region behind two side-by-side cylinders.


Author(s):  
N. Parameswara Rao ◽  
K. Arul Prakash

Numerical simulation of complex three-dimensional flow through the spiral casing has been studied using a finite element method. An explicit Eulerian velocity correction scheme has been employed to solve the Reynolds averaged Navier-stokes equations. The simulation has been performed to describe the flow in high Reynolds number (106) regime and two k-ε turbulence models (standard k-ε and RNG k-ε) have been used for computing the turbulent flow. A streamline upwind Petrov Galerkin technique has been used for spatial discretisation. The velocity field and the pressure distribution inside the spiral casing has been studied. It has been observed that very strong secondary flow is evolved on the cross-stream planes.


Author(s):  
Vijay Pappu ◽  
Prosenjit Bagchi

Three-dimensional computational modeling and simulation using front tracking method are presented on the motion of a deformable cell over an adhesive surface in a shear flow. The numerical method couples a Navier-Stokes flow solver with cell membrane mechanics, and a Monte Carlo simulation to capture stochastic formation and breakage of receptor/ligand bonds. The entire range of events during cell adhesion, namely, initial arrest of a free-flowing cell, slow rolling of an adherent cell, and detachment off the surface is simulated. Simulations are conducted to signify the role of hydrodynamic lift force that exists for a deformable particle in a wall-bounded flow. Three sets of numerical experiments are presented. In the first set, we consider the initial arrest of the cell, and show that the time needed for the cell to arrest increases with increasing Ca, but rapidly drops and saturates for higher bond strength. In the second set, we consider quasi-steady rolling motion of the cell, and predict the experimentally observed “stop and go” motion of the rolling leukocytes which is characterized by intermittent pauses and sudden jumps in cell velocity. In the third set we consider the detachment of the cell from the surface upon breakage of bonds. The bond strength needed to prevent the detachment of an adherent cell is computed and shown to be maximum for an intermediate Ca.


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