A FVM implementation and validation of non-local modeling for single- and two-phase granular flows

Author(s):  
Dorian Faroux ◽  
Kimiaki Washino ◽  
Takuya Tsuji ◽  
Toshitsugu Tanaka
2021 ◽  
Vol 249 ◽  
pp. 03025
Author(s):  
Dorian Faroux ◽  
Kimiaki Washino ◽  
Takuya Tsuji ◽  
Toshitsugu Tanaka

Additional to a behavior switching between solid-like and liquid-like, dense granular flows also present propagating grain size-dependent effects also called non-local effects. Such behaviors cannot be efficiently modeled by standard rheologies such as µ(I)-rheology but have to be dealt with advanced non-local models. Unfortunately, these models are still new and cannot be used easily nor be used for various configurations. We propose in this work a FVM implementation of the recently popular NGF model coupled with the VOF method in order to both make non-local modeling more accessible to everyone and suitable not only for single-phase flows but also for two-phase flows. The proposed implementation has the advantage to be extremely straightforward and to only require a supplementary stabilization loop compared to the theoretical equations. We then applied our new framework to both single and two-phase flows for validation.


2008 ◽  
Vol 75 (16) ◽  
pp. 4706-4720 ◽  
Author(s):  
F. Damhof ◽  
W.A.M. Brekelmans ◽  
M.G.D. Geers

Author(s):  
Jingsen Ma ◽  
Chao-Tsung Hsiao ◽  
Georges L. Chahine

Cavitating bubbly flows are encountered in many engineering problems involving propellers, pumps, valves, ultrasonic biomedical applications, … etc. In this contribution an OpenMP parallelized Euler-Lagrange model of two-phase flow problems and cavitation is presented. The two-phase medium is treated as a continuum and solved on an Eulerian grid, while the discrete bubbles are tracked in a Lagrangian fashion with their dynamics computed. The intimate coupling between the two description levels is realized through the local void fraction, which is computed from the instantaneous bubble volumes and locations, and provides the continuum properties. Since, in practice, any such flows will involve large numbers of bubbles, schemes for significant speedup are needed to reduce computation times. We present here a shared-memory parallelization scheme combining domain decomposition for the continuum domain and number decomposition for the bubbles; both selected to realize maximum speed up and good load balance. The Eulerian computational domain is subdivided based on geometry into several subdomains, while for the Lagrangian computations, the bubbles are subdivided based on their indices into several subsets. The number of fluid subdomains and bubble subsets are matched with the number of CPU cores available in a share-memory system. Computation of the continuum solution and the bubble dynamics proceeds sequentially. During each computation time step, all selected OpenMP threads are first used to evolve the fluid solution, with each handling one subdomain. Upon completion, the OpenMP threads selected for the Lagrangian solution are then used to execute the bubble computations. All data exchanges are executed through the shared memory. Extra steps are taken to localize the memory access pattern to minimize non-local data fetch latency, since severe performance penalty may occur on a Non-Uniform Memory Architecture multiprocessing system where thread access to non-local memory is much slower than to local memory. This parallelization scheme is illustrated on a typical non-uniform bubbly flow problem, cloud bubble dynamics near a rigid wall driven by an imposed pressure function.


2015 ◽  
Vol 38 (11) ◽  
Author(s):  
Mehdi Bouzid ◽  
Adrien Izzet ◽  
Martin Trulsson ◽  
Eric Clément ◽  
Philippe Claudin ◽  
...  

2015 ◽  
Vol 109 (2) ◽  
pp. 24002 ◽  
Author(s):  
Mehdi Bouzid ◽  
Martin Trulsson ◽  
Philippe Claudin ◽  
Eric Clément ◽  
Bruno Andreotti

2013 ◽  
Vol 50 (19) ◽  
pp. 2837-2845 ◽  
Author(s):  
Susanta Ghosh ◽  
Abhishek Kumar ◽  
Veera Sundararaghavan ◽  
Anthony M. Waas
Keyword(s):  

Author(s):  
Olivier Pouliquen ◽  
Yoel Forterre

A non-local theory is proposed to model dense granular flows. The idea is to describe the rearrangements occurring when a granular material is sheared as a self-activated process. A rearrangement at one position is triggered by the stress fluctuations induced by rearrangements elsewhere in the material. Within this framework, the constitutive law, which gives the relation between the shear rate and the stress distribution, is written as an integral over the entire flow. Taking into account the finite time of local rearrangements, the model is applicable from the quasi-static regime up to the inertial regime. We have checked the prediction of the model in two different configurations, namely granular flows down inclined planes and plane shear under gravity, and we show that many of the experimental observations are predicted within the self-activated model.


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