Handling Slender/Thin Geometries with Sharp Edges in Sharp Interface Immersed Boundary Approach

2020 ◽  
pp. 139-165
Author(s):  
Pradeep Kumar Seshadri ◽  
Ashoke De
Keyword(s):  
Sharp Interface ◽  
Immersed Boundary ◽  
Sharp Edges

Role of solution reconstruction in hypersonic viscous computations using a sharp interface immersed boundary method

2021 ◽  
Vol 103 (4) ◽  
Author(s):  
Shuvayan Brahmachary ◽  
Ganesh Natarajan ◽  
Vinayak Kulkarni ◽  
Niranjan Sahoo ◽  
V. Ashok ◽  
...  
Keyword(s):  
Immersed Boundary Method ◽  
Sharp Interface ◽  
Immersed Boundary ◽  
Boundary Method

Comparison of Sharp Interface and Smoothed Profile Methods for Laminar Flow Analysis Over Stationary and Moving Boundaries

2014 ◽  
Author(s):  
Fazlolah Mohaghegh ◽  
John Mousel ◽  
H. S. Udaykumar
Keyword(s):  
Drag Coefficient ◽  
Immersed Boundary Method ◽  
Flow Analysis ◽  
Sharp Interface ◽  
Wake Flow ◽  
Immersed Boundary ◽  
Particulate Flows ◽  
Sharp Interface Method ◽  
Smoothed Profile Method ◽  
Coarse Grids

This study is a comparison of two techniques for simulation of particulate flows on fixed Cartesian grids: Sharp interface Method (SIM) (Udaykumar et al., 2001, 2002, 2003) and a modified version of Immersed Boundary Method (Peskin, 1977) (IBM) known as Smoothed Profile Method (SPM) (Nakayama and Yamamoto, 2005; Luo et. al, 2009). Different cases were studied includes flow over one or two moving and stationary particles. Predictions of the drag coefficient shows that SPM and SIM are very close to the experiments. SIM slightly under-predicts the value of the drag coefficient while SPM has a small over-estimation. Moreover, SPM is more accurate on coarse grids. However, with refinement of the grid SIM approaches the exact values very fast leading to better results on fine grids. Flow pattern and vortex structures of SPM and SIM are almost the same. Both methods are capable of analyzing the wake flow. Unlike SIM, SPM is able to simulate the flow when two particles are in contact. When two particles are in motion and are very close in a way that the two interfaces overlap, SPM shows a repulsion force between two spheres which reduces the accuracy in comparison with SIM. However, SPM can achieve the collision of two particles without problem.

Large eddy simulation of an axial pump with coupled flow rate calculation using the sharp interface immersed boundary method

2019 ◽  
Vol 29 (7) ◽  
pp. 2253-2276
Author(s):  
Mohammad Haji Mohammadi ◽  
Joshua R. Brinkerhoff
Keyword(s):  
Large Eddy Simulation ◽  
Flow Rate ◽  
Immersed Boundary Method ◽  
Sharp Interface ◽  
Immersed Boundary ◽  
Inlet Flow ◽  
Content Type ◽  
Eddy Simulation ◽  
Inlet Flow Rate ◽  
Large Eddy

Purpose Turbomachinery, including pumps, are mainly designed to extract/produce energy from/to the flow. A major challenge in the numerical simulation of turbomachinery is the inlet flow rate, which is routinely treated as a known boundary condition for simulation purposes but is properly a dependent output of the solution. As a consequence, the results from numerical simulations may be erroneous due to the incorrect specification of the discharge flow rate. Moreover, the transient behavior of the pumps in their initial states of startup and final states of shutoff phases has not been studied numerically. This paper aims to develop a coupled procedure for calculating the transient inlet flow rate as a part of the solution via application of the control volume method for linear momentum. Large eddy simulation of a four-blade axial hydraulic pump is carried out to calculate the forces at every time step. The sharp interface immersed boundary method is used to resolve the flow around the complex geometry of the propeller, stator and the pipe casing. The effect of the spurious pressure fluctuations, inherent in the sharp interface immersed boundary method, is damped by local time-averaging of the forces. The developed code is validated by comparing the steady-state volumetric flow rate with the experimental data provided by the pump manufacturer. The instantaneous and time-averaged flow fields are also studied to reveal the flow pattern and turbulence characteristics in the pump flow field. Design/methodology/approach The authors use control volume analysis for linear momentum to simulate the discharge rate as part of the solution in a large eddy simulation of an axial hydraulic pump. The linear momentum balance equation is used to update the inlet flow rate. The sharp interface immersed boundary method with dynamic Smagorinsky sub-grid stress model and a proper wall model is used. Findings The steady-state volumetric flow rate has been computed and validated by comparing to the flow rate specified by the manufacturer at the simulation conditions, which shows a promising result. The instantaneous and time averaged flow fields are also studied to reveal the flow pattern and turbulence characteristics in the pump flow field. Originality/value An approach is proposed for computing the volumetric flow rate as a coupled part of the flow solution, enabling the simulation of turbomachinery at all phases, including the startup/shutdown phase. To the best of the authors’ knowledge, this is the first large eddy simulation of a hydraulic pump to calculate the transient inlet flow rate as a part of the solution rather than specifying it as a fixed boundary condition. The method serves as a numerical framework for simulating problems incorporating complex shapes with moving/stationary parts at all regimes including the transient start-up and shut-down phases.

scholarly journals A Coupled Sharp-Interface Immersed Boundary-Finite-Element Method for Flow-Structure Interaction With Application to Human Phonation

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
X. Zheng ◽  
Q. Xue ◽  
R. Mittal ◽  
S. Beilamowicz
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Flow Structure ◽  
Three Dimensional ◽  
Vocal Folds ◽  
Sharp Interface ◽  
Immersed Boundary ◽  
Three Dimensional Model ◽  
Structure Interaction ◽  
Element Method

A new flow-structure interaction method is presented, which couples a sharp-interface immersed boundary method flow solver with a finite-element method based solid dynamics solver. The coupled method provides robust and high-fidelity solution for complex flow-structure interaction (FSI) problems such as those involving three-dimensional flow and viscoelastic solids. The FSI solver is used to simulate flow-induced vibrations of the vocal folds during phonation. Both two- and three-dimensional models have been examined and qualitative, as well as quantitative comparisons, have been made with established results in order to validate the solver. The solver is used to study the onset of phonation in a two-dimensional laryngeal model and the dynamics of the glottal jet in a three-dimensional model and results from these studies are also presented.

Sharp interface immersed-boundary/level-set method for wave–body interactions

2009 ◽  
Vol 228 (17) ◽  
pp. 6590-6616 ◽  
Author(s):  
Jianming Yang ◽  
Frederick Stern
Keyword(s):  
Level Set Method ◽  
Level Set ◽  
Sharp Interface ◽  
Immersed Boundary
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