Bulletin of the American Physical Society
75th Annual Meeting of the Division of Fluid Dynamics
Volume 67, Number 19
Sunday–Tuesday, November 20–22, 2022; Indiana Convention Center, Indianapolis, Indiana.
Session L05: Biological Fluid Dynamics: General II |
Hide Abstracts |
Chair: Michael Plesniak, The George Washington University Room: 132 |
Monday, November 21, 2022 8:00AM - 8:13AM |
L05.00001: A comprehensive computational and experimental study of deep brain stimulation Jennifer Muller, siyu chen, Wen Sang, Rungun Nathan, Chenyuan Wu, Ani Ural, Qianhong Wu Deep brain stimulation (DBS) is an established treatment for Parkinson's disease, in which a radiofrequency (RF) probe is inserted and then removed from the brain prior to electrode localization. To improve the accuracy of clinical operations, it is critical to establish a better understanding of the dynamics of probe-tissue interactions. In this paper, we present a comprehensive computational and experimental study to simulate probe insertion and removel process. A dynamic explicit, Coupled-Eulerian-Lagrangian (CEL) based, linear finite element (FE) 3D model was constructed, which consisted of an RF probe and a 1.5% w/w agar gel block. For an insertion velocity consistent with the clinical application, the contact force and temporal-spacial opening and closing of the channel created by the RF proble, was predicted. Correspondingly, an experimental setup was developed. An RF probe, instumented with a load cell, was inserted into, and then revmoved from an agar gel block, at the same velocity as the FE model. The reaction force was measured which agrees with with the numerical simulation. A high-speed camera was used to capture the channel opening and closing, which also agrees with the FE simulation results, validating the numberal approach. The paper improves our understanding of the fluid-structure interaction between the RF probe and the the soft gel. It lays the foundation for a more comprehensive study of deep brain stimulation that involves real tissue properties. |
Monday, November 21, 2022 8:13AM - 8:26AM |
L05.00002: Microfluidic model of micro-haemodynamics in complex porous media Qi Chen, Naval Singh, Kerstin Schirrmann, Igor Chernyavsky, Anne Juel The human placenta relies on well-orchestrated haemodynamics to deliver its multiple functions. Its geometrical complexity and lack of appropriate animal models mean that laboratory models offer a powerful tool to investigate haemodynamics and haemorheology in the human placenta and other complex biological tissues. We develop a model of RBCs with polydimethylsiloxane (PDMS) capsules of adjustable diameter and membrane thickness, which are microfabricated using a 3D nested glass capillary device. The elastic modulus of the membrane can be varied by an order of magnitude by adjusting the chemistry and the capsules are further deflated by osmosis to match the surface-area-to-volume ratio of real RBCs. We test the aptitude of these capsules to mimic the motion and large deformations of single RBC and of suspensions of RBCs in straight capillaries and arrays of contractions and expansions. Planar porous media of controlled geometry, porosity and different levels of disorder are then constructed by positioning cylindrical pillars in different spatial arrangements within a Hele-Shaw cell. Capsule suspension flows in porous media are then characterised in terms of the dynamic distribution and flow resistance as functions of haematocrit, disorder of the medium and capillary number. |
Monday, November 21, 2022 8:26AM - 8:39AM |
L05.00003: Aqueous humor dynamics under segmental flow conditions Gregorio J Matrinez Sanchez, Carlos Escobar del Pozo, Jorge L Naude de la Llave, Jose A Rocha Medina Primary Open-Angle Glaucoma is an asymptomatic ocular disease and according to the World Health Organization, the pathology ranks the second place in order to cause of blindness worldwide. The causes that could lead to the development of Glaucoma are under discussion, but it is well-known that the main risk factor is high intraocular pressure; the intraocular pressure is depending on the aqueous humor resistance in the drainage system of the eye. |
Monday, November 21, 2022 8:39AM - 8:52AM |
L05.00004: Hydrodynamics of drinking straws and finite-length pipes Olivia Pomerenk Pipe flow is classically studied for extremes of flow speed and pipe length, but many practical situations in industry and nature involve intermediate Reynolds numbers and finite-length pipes. We carry out lab experiments and modeling that reveal the hydraulic laws applicable to these intermediate cases. We summarize our findings with a pipe flow map in which classical regimes of pipe flow occupy distinct territories separated by boundaries involving complexities such as flow development and transition. Our measurements show that drinking through a straw is a perfect example of the maximally complex case, and more generally, our model provides accurate estimates of the hydraulic resistance across pipe geometries and flow conditions. |
Monday, November 21, 2022 8:52AM - 9:05AM |
L05.00005: A mathematical model for cell proliferation in a tissue-engineering scaffold pore Pejman Sanaei, Haniyeh Fattahpour In a tissue-engineering scaffold pore lined with cells, nutrient-rich culture medium flows through the scaffold and cells proliferate. In this process, both environmental factors such as flow rate, scaffold elasticity, as well as cell properties have significant effects on tissue growth. Recent studies focused on effects of scaffold pore geometry, elasticity and nutrient depletion on tissue growth seperatley, while in this work, we focus on all of these effects togetther. Our objectives are threefold: (i) design a mathematical model for the cell proliferation describing fluid dynamics, scaffold elasticity, nutrient concentration and tissue growth; (ii) solve the models and then simulate the tissue proliferation process; (iii) design a `reverse algorithm' to find the initial configuration of the scaffold with the knowledge of the desired property of the final tissue geometry. Our model reduces the numerical burdens and captures the experimental observations from the literature. In addition, it provides an efficient algorithm to simulate the cell proliferation and determine the design of a tissue engineering scaffold given a desired tissue profile outcome. |
Monday, November 21, 2022 9:05AM - 9:18AM |
L05.00006: An experimental and numerical study on the predictive aortic emboli trajectory mapping and optimization in ventricular assist device settings Hamid Mansouri, Muaz Kemerli, Robroy MacIver, Omid Amili Particle-laden flows in cardiovascular settings, especially in the aorta, are inherently challenging to study due to the presence of a high Reynolds number flow regime combined with a mix of large Stokes number embolic particles in a complex geometry. In continuation of our work presented last year, we perform a systematic mapping of inertial particles in four patient-specific aortic models grafted with the cannula of a left ventricular assist device (LVAD). This study experimentally and numerically investigates the Lagrangian particle trajectories in order to develop a predictive model for the fate of embolic particles at two clinically relevant flow rates. High-precision thin-wall phantoms of such models are 3D-printed and placed in a flow loop providing physiological flow conditions. Precision fluorescent beads ranging from 0.4 to 1.2 mm, replicating thrombi transport, are illuminated by a set of near-UV laser and LED light sources. The time-resolved particle tracking velocimetry (PTV) results are complemented by several hemodynamic parameters from a set of CFD simulations. The carefully validated numerical simulations based on our well-controlled experimental boundary conditions shed light on the appropriate choice of particle modeling approaches and numerical solver schemes. |
Monday, November 21, 2022 9:18AM - 9:31AM |
L05.00007: A computational approach for modeling flow through compliant vessels Oleksander Krul, Prosenjit Bagchi We present a computational approach for modeling unsteady flow through compliant vessels with hyperviscoelastic wall at small to moderate fluid inertia (Re = 0.1 to 100, based on vessel radius and entering fluid velocity). Our methodology is based on a hybrid of sharp-interface (ghost-node) and diffuse-interface immersed-boundary methods for fluid/wall interaction, finite-volume/spectral method-based flow solver, and finite-element method for wall mechanics. It allows us to simulate both large inflation (nearly twice increase in vessel radius) and complex collapse (high buckling modes and irregular buckled shape) under different constitutive models (linear elastic, strain softening, strain hardening) for the wall. For the inflating vessel, comparison is presented against classical (e.g., law of Laplace) and analytical theories. At lower Re, the maximum deformation occurs near the upstream end, but with increasing Re it occurs further downstream and a recirculation region appears. For the collapsible vessel, comparison is presented against Timoshenko’s theory for multi-lobed buckled shapes, as well as the post-buckling behavior of two-lobed shapes. Constitutive models are seen to have a significant effect on the inflated shape, but not on the buckled shape. |
Monday, November 21, 2022 9:31AM - 9:44AM Author not Attending |
L05.00008: Fluid dynamics of injection of neural precursor cells Michelle Beaulieu, Douglas H Kelley Therapeutic methods in development for treating various neurodegenerative diseases involve the injection of neural precursor cells directly into the brain. In this project, we seek to characterize and optimize injection parameters such as flow rate to ensure the safety and effectiveness of the procedure. Since the injection is an open-skull procedure, cell suspensions must be delivered quickly. However, if cells are forced to flow too quickly through the catheter, the shear stresses may damage or kill cells, as well as cause cell clusters to break apart. To identify acceptable injection flow rates, we drive a suspension of cells through the catheter at varying known rates, and quantify the impact on cell viability through measurements of the fraction of cells killed, the damage to cell structures, and the sizes of any remaining cell clusters. Further work will include investigations into other injection parameters, such as techniques for ensuring well-controlled volumes of cell suspension. |
Monday, November 21, 2022 9:44AM - 9:57AM |
L05.00009: Surface tension barrier for juvenile flying fish Hao-Ping Wang, Patricia Yang Flying fish penetrate the air-water surface before they fly. Due to the surface tension, the juvenile flying fish measured within 0.4 mm in length fail to leap out of the water surface (Yang et al., APS DFD, 2013)[1]. In this experimental study, we use styrofoam spheres to mimic juvenile flying fish and investigate the process of penetrating air-water surface. The penetrating process depends on the size of the sphere: About 20 mm is the critical diameter. Spheres smaller than this diameter can not break the water surface. Our analytical model suggests that this critical diameter of spheres is around 6 mm, which is one-third of the experimental results. The inconsistency is possibly due to the surface properties of the styrofoam spheres. Understanding the leaping process of juvenile flying fish may shed light on the design of micro aero-hydro vehicles. |
Monday, November 21, 2022 9:57AM - 10:10AM |
L05.00010: Spreading and drying of human blood pools Houssine Benabdelhalim, David Brutin The drying of whole human blood pools was studied under controlled humidity and imposed temperature conditions in a laboratory glove box. A blood pool represents an accumulation of blood on a substrate, and here blood is assimilated to a complex fluid made of several bio-colloids. We performed experiments at temperatures of 21 °C, 29 °C, and 37 °C, and relative humidity ranging from 20 % to 70 %. The air inside the glove box was still, and the evaporation process was mainly purely diffusive. A human blood diffusion coefficient of (1.08±0.02)×10-9 m2/s was obtained. Moreover, we elaborated an updated model using Page's model to describe the drying kinetics of human blood pools. The effect of the surface area of pools was considered using a diffusive characteristics time. The drying of human whole blood pools has been studied experimentally to improve the understanding of drops and pools of whole human blood. These findings are of interest for biomedical and forensic applications. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700