Graduate Thesis Or Dissertation
 

Modeling of Non-Spherical Particle Dynamics in a Non-Uniform Flow

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/zk51vr29m

Descriptions

Attribute NameValues
Creator
Abstract
  • Turbulent flow with suspended, non-spherical particles can be found in nature and several industrial applications. Although turbulence with dispersed spherical particles has been studied extensively, modeling the dynamics of non-spherical particles in a turbulent flow has not been studied extensively. Motion of spherical particles in complex flows is typically captured using the point-particle model wherein the particle is assumed small compared to the smallest flow scale, and closure models are used for forces acting on the particle. In order to capture the dynamics of ellipsoidal particles, the point-particle model is extended to account for the particle orientation relative to the flow and its effect on the closure models for forces on the particle. A one-way coupled direct numerical solver for motion of ellipsoidal particles is developed, verified and validated for simple test cases involving settling of particle around a stationary Gaussian vortex. The validated solver is then used to investigate the settling dynamics of non-spherical and spherical particle in a cellular vortical flow. As the first step, a stationary Taylor-Green vortex flow is used and can be thought of as a single eddy in turbulent flow. The strength and size of the vortex can be varied relative to the settling speed of the particle in order to investigate the effect of turbulence intensity on particle settling speeds for different aspect ratio of ellipsoidal particles. For weak vortex strength, the particle settling speeds are comparable to those in quiescent fluid. As the vortex strength is increased, the normalized particle settling speed decreased for different aspect ratios owing to vortex trapping. With further increase in the vortex strength, the normalized settling speed increased due to the fast tracking mechanism as the particles would traverse a path of least resistance. The Lagrangian trajectory, velocity, angular velocity, and orientation were analyzed in detail. The trends show that the settling speed of a particle in vortical flows depends on vortex strength relative to the settling speed in quiescent fluid and are influenced by the initial location relative to the vortex core as well as the shape factor. The developed model can be easily coupled with any fluid flow solver and used to study dynamics of particle motion in complex turbulent flows.
License
Resource Type
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Rights Statement
Publisher
Peer Reviewed
Language

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details AlshehriAhmad2023.pdf 2023-07-03 Public Download