A variationally bounded scheme for delayed detached eddy simulation: Application to vortex-induced vibration of offshore riser

Joshi, Vaibhav; Jaiman, Rajeev K.

doi:10.1016/j.compfluid.2017.08.013

Cited by 31 publications

(31 citation statements)

References 46 publications

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“…We observe more intense vortical structures near the location of large response amplitude. A more detailed analysis of the response amplitude and its relation to the trajectories along the riser can be found in [53]. This demonstration concludes that the present solver with common-refinement scheme is able to capture the physics as well as the response of the flexible riser reasonably well for non-matching unstructured meshes.…”

Section: Vortex Patternssupporting

confidence: 52%

A 3D common-refinement method for non-matching meshes in partitioned variational fluid–structure analysis

Law

Joshi

et al. 2018

Journal of Computational Physics

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We present a three-dimensional (3D) common-refinement method for non-matching meshes between discrete non-overlapping subdomains of incompressible fluid and nonlinear hyperelastic structure. The fluid flow is discretized using a stabilized Petrov-Galerkin method, and the large deformation structural formulation relies on a continuous Galerkin finite element method. An arbitrary Lagrangian-Eulerian formulation with a nonlinear iterative force correction (NIFC) coupling is achieved in a staggered partitioned manner by means of fully decoupled implicit procedures for the fluid and solid discretizations. To begin, we first investigate the accuracy of common-refinement method (CRM) to satisfy traction equilibrium condition along the fluid-elastic interface with non-matching meshes. We systematically assess the accuracy of CRM against the matching grid solution by varying grid mismatch between the fluid and solid meshes over a cylindrical tubular elastic body. We demonstrate second-order accuracy of CRM through uniform refinements of fluid and solid meshes along the interface. We then extend the error analysis to transient data transfer across non-matching meshes between fluid and solid solvers. We show that the common-refinement discretization across non-matching fluid-structure grids yields accurate transfer of the physical quantities across the fluid-solid interface. We next solve a 3D benchmark problem of a cantilevered hyperelastic plate behind a circular bluff body and verify the accuracy of coupled solutions with respect to the available solution in the literature. By varying the solid interface resolution, we generate various non-matching grid ratios and quantify the accuracy of CRM for the nonlinear structure interacting with a laminar flow. We illustrate that the CRM with the partitioned NIFC treatment is stable for low solid-to-fluid density ratio and non-matching meshes. Finally, we demonstrate the 3D parallel implementation of common-refinement with NIFC scheme for a realistic engineering problem of drilling riser undergoing complex vortex-induced vibration with strong added mass effects.

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Section: Vortex Patternssupporting

confidence: 52%

A 3D common-refinement method for non-matching meshes in partitioned variational fluid–structure analysis

Law

Joshi

et al. 2018

Journal of Computational Physics

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“…Compared to direct numerical simulation (DNS) and large eddy simulation (LES) methods, the delayed detached eddy simulation (DDES) method has significant advantages to save the computational resources while keeping the reasonable accuracy for the separated turbulent flow, as demonstrated by [44] for large-scale fluid-structure simulations. The DDES model offers an effective and reasonable way to simulate the vortex structures played during a flapping flight, hence we employ this model in our computational framework.…”

Section: Aspects Of Computational Modelingmentioning

confidence: 99%

A novel 3D variational aeroelastic framework for flexible multibody dynamics: Application to bat-like flapping dynamics

Law

Jaiman

2019

Computers & Fluids

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We present a novel three-dimensional (3D) variational aeroelastic framework for flapping wing with a flexible multibody system subjected to an external incompressible turbulent flow. The proposed aeroelastic framework consists of a threedimensional fluid solver with a hybrid RANS/LES model based on the delayed detached eddy simulation (DDES) treatment and a nonlinear monolithic elastic structural solver for the flexible multibody system with constraints. Radial basis function (RBF) is applied in this framework to transfer the aerodynamic forces and structural displacements across the discrete non-matching interface meshes while satisfying a global energy conservation. For the consistency of the interface data transfer process, the mesh motion of the fluid domain with large elastic deformation due to high-amplitude flapping motion is also performed via the standard radial basis functions. The fluid equations are discretized using a stabilized Petrov-Galerkin method in space and the generalized-α approach is employed to integrate the solution in time. The flexible multibody system is solved by using geometrically exact co-rotational finite element method and an energy decaying scheme is used to achieve numerical stability of the multibody solver with constraints. A nonlinear iterative force correction (NIFC) scheme is applied in a staggered partitioned iterative manner to maintain the numerical stability of aeroelastic coupling with strong arXiv:1807.04411v1 [physics.flu-dyn] 12 Jul 2018 added mass effect. An isotropic aluminum wing with flapping motion is simulated via the proposed aeroelastic framework and the accuracy of the coupled solution is validated with the available experimental data. We next study the robustness and reliability of the 3D flexible multibody aeroelastic framework for an anisotropic flapping wing flight involving battens and membranes with composite material and compare against the experimental results. Finally, we demonstrate the aeroelastic framework for a bat-like wing and examine the effects of flexibility on the flapping wing dynamics.

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“…Apart from the high density ratio between the two phases, ie,

ρ^{*} = ρ_{1}^{normalf} false/ ρ_{2}^{normalf} = 833.3

, a low structure‐to‐fluid density ratio

false(ρ^{s} false/ ρ_{1}^{normalf} = 0.5 false)

based on the denser fluid has been chosen. The initial condition for the order parameter is given as

ϕ false(x, y, 0 false) = - \tanh ((), \frac{y}{\sqrt{2} ϵ}) .

We have employed the hybrid RANS/LES model discussed in the work of Joshi and Jaiman for modeling the turbulent effects. The Reynolds number is defined based on the maximum velocity achieved by the cylinder and its diameter with respect to the denser fluid, ie,

R e = ρ_{1}^{normalf} U_{c y l} D false/ μ_{1}^{normalf} \approx 30, 000

.…”

Section: Numerical Testsmentioning

confidence: 99%

A hybrid variational Allen‐Cahn/ALE scheme for the coupled analysis of two‐phase fluid‐structure interaction

Joshi

Jaiman

2018

Numerical Meth Engineering

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Summary We present a partitioned iterative formulation for the modeling of fluid‐structure interaction (FSI) in two‐phase flows. The variational formulation consists of a stable and robust integration of three blocks of differential equations, viz, an incompressible viscous fluid, a rigid or flexible structure, and a two‐phase indicator field. The fluid‐fluid interface between the two phases, which may have high density and viscosity ratios, is evolved by solving the conservative phase‐field Allen‐Cahn equation in the arbitrary Lagrangian‐Eulerian coordinates. While the Navier‐Stokes equations are solved by a stabilized Petrov‐Galerkin method, the conservative Allen‐Cahn phase‐field equation is discretized by the positivity preserving variational scheme. Fully decoupled implicit solvers for the two‐phase fluid and the structure are integrated by the nonlinear iterative force correction in a staggered partitioned manner and the generalized‐α method is employed for the time marching. We assess the accuracy and stability of the phase‐field/ALE variational formulation for two‐ and three‐dimensional problems involving the dynamical interaction of rigid bodies with free surface. We consider the decay test problems of increasing complexity, namely, free translational heave decay of a circular cylinder and free rotation of a rectangular barge. Through numerical experiments, we show that the proposed formulation is stable and robust for high density ratios across fluid‐fluid interface and for low structure‐to‐fluid mass ratio with strong added‐mass effects. Overall, the proposed variational formulation produces results with high accuracy and compares well with available measurements and reference numerical data. Using unstructured meshes, we demonstrate the second‐order temporal accuracy of the coupled phase‐field/ALE method via decay test of a circular cylinder interacting with the free surface. Finally, we demonstrate the three‐dimensional phase‐field FSI formulation for a practical problem of internal two‐phase flow in a flexible circular pipe subjected to vortex‐induced vibrations due to external fluid flow.

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A variationally bounded scheme for delayed detached eddy simulation: Application to vortex-induced vibration of offshore riser

Cited by 31 publications

References 46 publications

A 3D common-refinement method for non-matching meshes in partitioned variational fluid–structure analysis

A 3D common-refinement method for non-matching meshes in partitioned variational fluid–structure analysis

A novel 3D variational aeroelastic framework for flexible multibody dynamics: Application to bat-like flapping dynamics

A hybrid variational Allen‐Cahn/ALE scheme for the coupled analysis of two‐phase fluid‐structure interaction

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