Simulations of Aerodynamic Separated Flows Using the Lattice Boltzmann Solver XFlow

Chávez-Módena, Miguel; Martínez, Javier Yangüela; Cabello, Jose Alberto; Ferrer, Esteban

doi:10.3390/en13195146

Cited by 27 publications

(14 citation statements)

References 48 publications

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“…Unlike conventional numerical schemes based on discretization of macroscopic Navier-Stokes equations, LBM is based on microscopic models. LBM works on a spatial discretization named lattice, consisting of a Cartesian distribution of discrete points with a discrete set of velocity directions e i (i = 1, … ,b), and has successfully simulated a range of flow conditions, including porous media, human blood flow, vortex shedding, multiphase flows, droplet dynamics and turbulent flows [29][30][31][32][33][34][35][36]. The Boltzmann transport equations in the continuum space can be written as follows:…”

Section: Numerical Simulation Methodsmentioning

confidence: 99%

Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

et al. 2021

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Dragonflies possess two pairs of wings and the interactions between forewing (FW) and hindwing (HW) play an important role in dragonfly flight. The effects of tandem-wing (TW) interactions on the aerodynamic performance of dragonfly hovering have been investigated. Numerical simulations of single-wing hovering without interactions and TW hovering with interactions are conducted and compared. It is found that the TW interactions reduce the lift coefficient of FW and HW by 7.36% and 20.25% and also decrease the aerodynamic power and efficiency. The above effects are mainly caused by the interaction between the vortex structures of the FW and the HW, which makes the pressure of the wing surface and the flow field near the wings change. During the observations of dragonfly flight, it is found that the phase difference ( γ ) is not fixed. To explore the influence of phase difference on aerodynamic performance, TW hovering with different phase differences is studied. The results show that at γ = 22.5°, dragonflies produce the maximum lift which is more than 20% of the body weight with high efficiency; at γ = 180°, dragonflies generate the same lift as the body weight.

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Section: Numerical Simulation Methodsmentioning

confidence: 99%

Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

et al. 2021

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“…Despite their wide usage, Navier–Stokes solvers suffer from drawbacks, such as complex meshing and highly empirical turbulence modeling. Unlike conventional CFD techniques, the lattice Boltzmann formulation utilized in the XFlow solver offers significant benefits to complex mesh problems and standard turbulence models, such as the Reynolds-averaged Navier–Stokes equations ( Holman et al, 2012 ; Chávez-Modena et al, 2020 ). In this simulation, blood was modeled as a Newtonian incompressible fluid with a density of 1,050 kg/m 3 and a viscosity of 0.0035 Pas.…”

Section: Methodsmentioning

confidence: 99%

A Multi-Domain Simulation Study of a Pulsatile-Flow Pump Device for Heart Failure With Preserved Ejection Fraction

2022

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Mechanical circulatory support (MCS) devices are currently under development to improve the physiology and hemodynamics of patients with heart failure with preserved ejection fraction (HFpEF). Most of these devices, however, are designed to provide continuous-flow support. While it has been shown that pulsatile support may overcome some of the complications hindering the clinical translation of these devices for other heart failure phenotypes, the effects that it may have on the HFpEF physiology are still unknown. Here, we present a multi-domain simulation study of a pulsatile pump device with left atrial cannulation for HFpEF that aims to alleviate left atrial pressure, commonly elevated in HFpEF. We leverage lumped-parameter modeling to optimize the design of the pulsatile pump, computational fluid dynamic simulations to characterize hydraulic and hemolytic performance, and finite element modeling on the Living Heart Model to evaluate effects on arterial, left atrial, and left ventricular hemodynamics and biomechanics. The findings reported in this study suggest that pulsatile-flow support can successfully reduce pressures and associated wall stresses in the left heart, while yielding more physiologic arterial hemodynamics compared to continuous-flow support. This work therefore supports further development and evaluation of pulsatile support MCS devices for HFpEF.

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“…More precisely, these collision models include standard operators such as the BGK operator with a weighted secondorder equilibrium (BGK-W2 [33]), a non-weighted fourth-order equilibrium (BGK-NW4 [31,34]), and the tworelaxation-time formulation (TRT [29,35]). In addition, multi-relaxation-time collision models based on raw (RM [36,37,38]), Hermite (HM [39,40,41,42]), central (CM [43,44,45,34]), central Hermite (CHM [46,47,48]) moment spaces, as well as cumulants (K [49,50,51,52]), are further considered. Finally, a multi-relaxation-time formulation of the recursive regularized (RR) collision model is included due to its interesting stability property [53,54,55,56,57].…”

Section: Lb Collision Modelsmentioning

confidence: 99%

Cross-platform programming model for many-core lattice Boltzmann simulations

2021

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We present a novel, hardware-agnostic implementation strategy for lattice Boltzmann (LB) simulations, which yields massive performance on homogeneous and heterogeneous many-core platforms. Based solely on C++17 Parallel Algorithms, our approach does not rely on any language extensions, external libraries, vendor-specific code annotations, or pre-compilation steps. Thanks in particular to a recently proposed GPU back-end to C++17 Parallel Algorithms, it is shown that a single code can compile and reach state-of-the-art performance on both many-core CPU and GPU environments for the solution of a given non trivial fluid dynamics problem. The proposed strategy is tested with six different, commonly used implementation schemes to test the performance impact of memory access patterns on different platforms. Nine different LB collision models are included in the tests and exhibit good performance, demonstrating the versatility of our parallel approach. This work shows that it is less than ever necessary to draw a distinction between research and production software, as a concise and generic LB implementation yields performances comparable to those achievable in a hardware specific programming language. The results also highlight the gains of performance achieved by modern many-core CPUs and their apparent capability to narrow the gap with the traditionally massively faster GPU platforms. All code is made available to the community in form of the open-source project stlbm, which serves both as a stand-alone simulation software and as a collection of reusable patterns for the acceleration of pre-existing LB codes.

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Simulations of Aerodynamic Separated Flows Using the Lattice Boltzmann Solver XFlow

Cited by 27 publications

References 48 publications

Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

A Multi-Domain Simulation Study of a Pulsatile-Flow Pump Device for Heart Failure With Preserved Ejection Fraction

Cross-platform programming model for many-core lattice Boltzmann simulations

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