Many industrial fluid flow problems involve the interaction between heavy, rigid objects and one or more fluid phases. For several decades, there has been a vested interest in simulating these fluid-structure interaction (FSI) problems in order to improve engineering design processes. However, numerical simulations of these problems can be challenging and computationally expensive due to the complexity and multiphysics nature of the governing partial differential equations. This thesis presents a robust, adaptive numerical technique for simulating high density ratio and high shear multiphase flows. The method is second-order accurate and stable for density and viscosity ratios of up to one million, and employs the level set approach to resolve topologically complex interfaces. This incompressible flow solver is coupled to a constraint-based immersed body method, enabling efficient simulation of rigid, multiphase fluid-structure interaction. Adaptive mesh refinement is used to deploy fine grid resolution in parts of the domain requiring more accuracy, such as fluid-solid or fluid-gas interfaces and regions of high vorticity. A variety of two- and three-phase fluid flow problems are simulated to demonstrate the wide applicability of the technique. Additionally, this thesis presents an efficient post-processing approach for computing hydrodynamic forces and torques on immersed bodies and investigates optimality in aquatic locomotion for undulatory swimmers.

Creator

• Nangia, Nishant

DOI

• https://doi.org/10.21985/n2-sq8c-nc53

Subject

• Applied mathematics
• Computational physics
• Fluid mechanics

Language

• en

Alternate Identifier

• etdadmin_upload_637421
• http://dissertations.umi.com/northwestern:14506

Keyword

• Aquatic locomotion
• Adaptive mesh refinement
• Fluid-structure interaction
• Multiphase flow
• Computational fluid dynamics
• Vehicle aerodynamics

Date created

• 2019-01-01

Resource type

• Dissertation

Rights statement

• In Copyright