Bulletin of the American Physical Society
74th Annual Meeting of the APS Division of Fluid Dynamics
Volume 66, Number 17
Sunday–Tuesday, November 21–23, 2021; Phoenix Convention Center, Phoenix, Arizona
Session M18: Particleladen Flows: Clustering and Heat Transfer 
Hide Abstracts 
Chair: Peter Vorobieff, University of New Mexico Room: North 131 C 
Monday, November 22, 2021 1:10PM  1:23PM 
M18.00001: Quantification of Inertial Particle Clustering and Geometric Confinement Effects in Turbulent Flow Through a Porous Cell Xiaoliang He, Thibault OUJIA, Benjamin Kadoch, Keigo Matsuda, Kai Schneider, Sourabh V Apte Quantifying how turbulence affects inertial particle clustering, migration, and deposition within confined geometries of porous beds is of importance in several applications such as hyporheic exchange of river beds, gravel packs in enhanced oil recovery, among others. Direct numerical simulation is performed to investigate effect of turbulent flow in a face centered cubic porous unit cell on the transport of inertial particles at different Stokes numbers (0.01, 0.1, 0.5, 1, and 2) and at a pore Reynolds number of 500. Particles are advanced using oneway coupling and collision of particles with pore walls is modeled as perfectly elastic specular reflection. Statistics on Voronoi tessellation volume and its divergence are used to quantify clustering, void formation, and effect of geometric confinement. The general features of cluster and void formation are similar to those in forced, isotropic turbulence, but some very fine scale clusters are developed owing to collisions with wall. Multiscale wavelet analysis also shows signature of the confined geometry on the scale dependent energy spectra of number density. 
Monday, November 22, 2021 1:23PM  1:36PM 
M18.00002: Tracking particle clusters in turbulent channel flows via densitybased clustering algorithms Tuhin Bandopadhyay, Laura Villafane The dynamics of clusters of inertial particles in a fully developed turbulent flow are analyzed using a new methodology for cluster identification and temporal tracking. It builds on densitybased clustering algorithms DbScan and Optics to identify particle clusters from 3D snapshots of dispersed particles, which are then defined in terms of skeleton markers and boundary particles. Tracking and connectivity of cluster markers in snapshots from sequential time steps provide a computationally efficient tool to study the cluster dynamics. The computational cost of the new methodology is compared to that of conventional Voronoi tessellations. We apply these tools to study the evolution of clusters in a particleladen turbulent squareduct flow, using data from DNS simulations with pointparticle Lagrangian models. By tracking in time information of individual clusters such as their volume and location of constituent markers we analyze the different formation and disintegration processes, i.e. break up and merging of clusters, coagulation or dispersal of particles not assigned to clusters in previous or later times. Spatial information encoded in the cluster labeled markers facilitates the analysis of spatial and temporal correlations between clusters and flow dynamics. 
Monday, November 22, 2021 1:36PM  1:49PM 
M18.00003: Preferential alignment and heterogeneous distribution of active nonspherical swimmers near Lagrangian coherent structures Lei Fang, Xinyu Si We report the interaction between active nonspherical swimmers and a longstanding flow structure, Lagrangian coherent structures (LCSs), in a weakly turbulent twodimensional particleladen flow. Using a hybrid experimentalnumerical model, we show that rodlike swimmers have a much stronger and more robust preferential alignment with attracting LCSs than with repelling LCSs. Tracing the swimmers' Lagrangian trajectories, we reveal that the preferential alignment is the consequence of the competition between the intrinsic mobility of the swimmers and the reorientation ability of the strain rate near the attracting LCSs. The strong preferential alignment with attracting LCSs further leads to a strong clustering near the attracting LCSs. Moreover, we show the selfsimilarity of this clustering, which reduces the intricate interaction to only one control parameter. Our results generically elucidate the interaction between active and nonspherical swimmers with LCSs and, thus, can be widely applied to many natural and engineered fluids. 
Monday, November 22, 2021 1:49PM  2:02PM 
M18.00004: Spatial Relationships Between Large Scale Particle Clusters and Momentum Structures Guangyao Cui, Ido Ruhman, Ian Jacobi The clustering behavior of inertial particles in a turbulent boundary layer was studied experimentally at the scale of the natural largescale motions (LSMs) of the momentum field. A new, waveletbased hierarchy detection tool was employed to identify largescale coherent clusters of particles, instantaneously. Significant particle clustering at scales of two to three times the boundary layer thickness was observed, with a dominant orientation in the streamwise direction. Conditional averaging was then used to determine the typical coherent motions associated with the largescale clusters. The influence of LSMs on the size, orientation, and hierarchical organization of particle clusters was explored. 
Monday, November 22, 2021 2:02PM  2:15PM 
M18.00005: The Application of a NonIntrusive Particle Temperature Measurement Methodology for an Onsun Falling Particle Receiver Jesus D Ortega, Guillermo Anaya, Peter Vorobieff, Clifford K Ho, Gowtham Mohan Falling particle receivers (FPR) such as the one at Sandia National Labs, represent the stateoftheart Concentrating Solar Power (CSP) technology for energy harvesting. FPR operate by creating a gravitydriven particle curtain which is directly used a transport and storage media for concentrated light. A system paired with an appropriate Brayton power loop is capable of achieving thermaltoelectric conversion efficiencies when operating at temperatures greater than 700 C. However, the FPR presents a unique challenge to the CSP field as the complex coupling of multiple variables, such as particle temperature, wind speed and direction, etc., can impact its thermal performance as advective losses can be strongly present on the system. This work presents the continuation of a series of improvement to a nonintrusive methodology using a highspeed IR camera and a visiblelight camera (Nikon D3500) to accomplish this indirect particle temperature measurement, which in turn is used to estimate the heat losses of the receiver. Six variables were considered to study their relative impact towards the receiver efficiency by means of an ANOVA analysis to further understand the importance of mitigating these variable to increase the receiver efficiency. 
Monday, November 22, 2021 2:15PM  2:28PM Not Participating 
M18.00006: Heat Transfer Measurements in Neutrally Buoyant Suspensions in the Inertial Regime Merin A.P., Vinod Srinivasan Recent interest in dense granular suspensions has focused on characterizing their rheology and modeling the viscosity, whereas little is known about other transport properties such as thermal diffusivity. The goal of this study is to understand the role of particle inertia and fluid turbulence on thermal transport in sheared granular suspensions. The study uses a TaylorCouette cell with a rotating outer cylinder and fixed inner cylinder to create a uniform shear flow. Spherical polystyrene beads of 2 mm were used to make a suspension with propylene glycol water mixture as the base fluid. Particle volume fractions in the range 550 % are studied. By changing the rotation speed, and therefore the shear rate, particle Reynolds numbers are varied from 0100, going from Stokes flow to turbulence with increasing inertia. We study the thermal diffusivity of the suspension by examining the decay of the inner wall temperature after a sharp thermal pulse has been applied. The thermal diffusivity is extracted from the observed temperature decay using a model for onedimensional diffusion into the particle suspension. A nonmonotonic behavior of thermal diffusivity with volume fraction is observed. 
Monday, November 22, 2021 2:28PM  2:41PM 
M18.00007: The effect of particle clustering on the thermal entrance length in moderately dense gassolid flows Sarah Beetham, AARON M LATTANZI, Jesse S Capecelatro We perform highlyresolved EulerianLagrangian simulations of moderately dense, gassolid flows to study the thermal entrance length. We show that strong momentum coupling between the phases results in the generation of dense particle clusters that leads to a 2–3 fold increase in the thermal entrance length, as compared to a uniform (perfectly mixed) distribution. The observed increase is found to be primarily due to the covariance between volume fraction and temperature fluctuations, referred to as the fluid drift temperature. Using scaling arguments and Gene Expression Programming, model closure is obtained in the context of a onedimensional averaged twofluid equation. 
Monday, November 22, 2021 2:41PM  2:54PM 
M18.00008: An AdvectionDiffusionReaction (ADR) Equation For Correcting The SelfInduced Velocity and Temperature Disturbances in EulerLagrange PointParticle Methods Sourabh V Apte In twoway coupled particleladen EulerLagrange simulations, the particles are assumed subgrid and their momentum and energy exchange with the surrounding fluid are modeled as point sources. For particles on the order of the grid resolution, this exchange introduces a local disturbance in the fluid flow that can substantially alter their undisturbed values needed for closure models, resulting in significant errors in the particle dynamics. To correct for this disturbance, advectiondiffusionreaction (ADR) equations are derived for the momentum and heat transfer and solved in addition to the standard conservation equations in twoway coupling. An embedded voxel based approach is used in a small region of influence surrounding each particle to solve these equations and to correct for their selfdisturbance. Tests are performed to show that the approach is applicable to arbitrary shaped grids, range of Reynolds and Pectlet numbers, different EulerLagrange interpolation kernels, and catpturing hydrodynamic effects of neighboring particles in multipleparticle systems. The newly developed approach is accurate, easy to implement in any flow solver, and affordable. 
Monday, November 22, 2021 2:54PM  3:07PM 
M18.00009: Determination of aerodynamic and themal correlations for ellipsoidal particles via direct numerical simulation Wolfgang Schröder, Konstantin Fröhlich, Thede Kiwitt, Matthias Meinke

Monday, November 22, 2021 3:07PM  3:20PM 
M18.00010: LBMDEMFEM coupling model: an efficient FSI method to investigate convective heat transfer through nonspherical particle suspensions with particle rotations Qiya Shu Motivation: Sheardriven particle rotation influences heat transfer at high Peclet number (Shu et al., 2021). For nonspherical particles, the shearinduced movements are much more complicated including motions like tumbling and kayaking. The calculation of both the fluidstructure interaction and the twophase heat transfer requires precise and efficient numerical methods. This study presents an approach to simulate particle movement and heat transfer by a combination of the Lattice Boltzmann method (LBM, for mass and heat flow of the fluid), the Discrete Element method (DEM, for movement of the particles), and a FiniteElement approach (FEM, for heat flow inside the particle). 
Follow Us 
Engage
Become an APS Member 
My APS
Renew Membership 
Information for 
About APSThe American Physical Society (APS) is a nonprofit membership organization working to advance the knowledge of physics. 
© 2023 American Physical Society
 All rights reserved  Terms of Use
 Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 207403844
(301) 2093200
Editorial Office
1 Research Road, Ridge, NY 119612701
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700