PDAE Formulation for Multi-Domain Dynamic Systems With Application to Fluid-Structure Interactions in Arterial Hemodynamics

2000 ◽  
Author(s):  
Danielle C. Tarraf ◽  
H. Harry Asada
Keyword(s):  
Dynamical Systems ◽  
Dynamic Systems ◽  
Systematic Approach ◽  
Well Posedness ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Solution Approach ◽  
Arterial Hemodynamics ◽  
Consistent Initialization ◽  
Algebraic Constraints

Abstract A systematic approach to modeling coupled distributed dynamical systems by formulating them as partial differential equations and algebraic constraints (PDAEs) is presented. Several advantages of the PDAE formulation are listed and discussed. The challenges of ensuring well-posedness are also touched upon. The PDAE system is converted by semi-discretization into a corresponding DAE system. It is subsequently realized for the purpose of simulations using a recently emerging control based approach. Thus, the typical requirement of consistent initialization is avoided for a large class of systems. The PDAE formulation and the numerical solution approach are illustrated through a particular application: modeling of fluid-structure interactions in arterial hemodynamics.

scholarly journals Parallel time-stepping for fluid-structure interactions

2021 ◽  
Author(s):  
Thomas Richter ◽  
Nils Margenberg
Keyword(s):  
Stokes Equations ◽  
Numerical Test ◽  
Time Integration ◽  
Navier Stokes ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Solution Approach ◽  
Time Stepping ◽  
Parallel Time ◽  
Nicolson Scheme

We present a parallel time-stepping method for fluid-structure   interactions. The interaction between the incompressible   Navier-Stokes equations and a hyperelastic solid is formulated in a   fully monolithic framework. Discretization in space is based on   equal order finite element for all variables and a variant of the   Crank-Nicolson scheme is used as second order time integrator. To   accelerate the solution of the systems, we analyze a parallel-in   time method. For different numerical test cases in 2d and in 3d we   present the efficiency of the resulting solution approach. We also   discuss some challenges and limitations that are connected   to the special structure of fluid-structure interaction problem.   In particular, we will investigate stability and dissipation     effects of the time integration and their influence on the     convergence of the Parareal method. It turns out that especially     processes based on an internal dynamics (e.g. driven by the vortex     street around an elastic obstacle) cause great     difficulties. Configurations however, which are driven by     oscillatory problem data, are well-suited for parallel time     stepping and allow for substantial speedups.

Fluid-Structure Interactions

2009 ◽  
Author(s):  
Michael Paidoussis ◽  
Stuart Price ◽  
Emmanuel de Langre
Keyword(s):  
Fluid Structure Interactions ◽  
Fluid Structure

Experimental Mixing Parameterization Due to Multiphase Fluid � Structure Interactions

2010 ◽  
Vol 5 (2) ◽  
pp. 1-8
Author(s):  
Ranis N. Ibragimov ◽  
◽  
Akshin S. Bakhtiyarov ◽  
Margaret Snell ◽  
◽  
...  
Keyword(s):  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Multiphase Fluid

scholarly journals Numerical modeling in arterial hemodynamics incorporating fluid-structure interaction and microcirculation

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Fan He ◽  
Lu Hua ◽  
Tingting Guo
Keyword(s):  
Numerical Modeling ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Fluid Structure Interaction ◽  
Rigid Wall ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Arterial Hemodynamics ◽  
Wall Compliance ◽  
Wall Shear

Abstract Background The effects of arterial wall compliance on blood flow have been revealed using fluid-structure interaction in last decades. However, microcirculation is not considered in previous researches. In fact, microcirculation plays a key role in regulating blood flow. Therefore, it is very necessary to involve microcirculation in arterial hemodynamics. Objective The main purpose of the present study is to investigate how wall compliance affects the flow characteristics and to establish the comparisons of these flow variables with rigid wall when microcirculation is considered. Methods We present numerical modeling in arterial hemodynamics incorporating fluid-structure interaction and microcirculation. A novel outlet boundary condition is employed to prescribe microcirculation in an idealised model. Results The novel finding in this work is that wall compliance under the consideration of microcirculation leads to the increase of wall shear stress in contrast to rigid wall, contrary to the traditional result that wall compliance makes wall shear stress decrease when a constant or time dependent pressure is specified at an outlet. Conclusions This work provides the valuable study of hemodynamics under physiological and realistic boundary conditions and proves that wall compliance may have a positive impact on wall shear stress based on this model. This methodology in this paper could be used in real model simulations.

scholarly journals Cross-Flow Tidal Turbines with Highly Flexible Blades—Experimental Flow Field Investigations at Strong Fluid–Structure Interactions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 797
Author(s):  
Stefan Hoerner ◽  
Iring Kösters ◽  
Laure Vignal ◽  
Olivier Cleynen ◽  
Shokoofeh Abbaszadeh ◽  
...  
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Cross Flow ◽  
Speed Ratio ◽  
Fluid Structure Interactions ◽  
Dimensional Parameter ◽  
Fluid Structure ◽  
Passive Flow Control ◽  
Tidal Turbines ◽  
Tidal Turbine

Oscillating hydrofoils were installed in a water tunnel as a surrogate model for a hydrokinetic cross-flow tidal turbine, enabling the study of the effect of flexible blades on the performance of those devices with high ecological potential. The study focuses on a single tip-speed ratio (equal to 2), the key non-dimensional parameter describing the operating point, and solidity (equal to 1.5), quantifying the robustness of the turbine shape. Both parameters are standard values for cross-flow tidal turbines. Those lead to highly dynamic characteristics in the flow field dominated by dynamic stall. The flow field is investigated at the blade level using high-speed particle image velocimetry measurements. Strong fluid–structure interactions lead to significant structural deformations and highly modified flow fields. The flexibility of the blades is shown to significantly reduce the duration of the periodic stall regime; this observation is achieved through systematic comparison of the flow field, with a quantitative evaluation of the degree of chaotic changes in the wake. In this manner, the study provides insights into the mechanisms of the passive flow control achieved through blade flexibility in cross-flow turbines.

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