Mechanical Engineering ETDs

Publication Date

Spring 4-14-2019

Abstract

Turbulent mixing layers are a canonical free shear flow in which two parallel fluid streams of different velocities mix at their interface. Understanding spatial development of a turbulent mixing layer is essential for various engineering applications. However, multiple factors affect physics of this flow, making it difficult to reproduce results in experiments and simulations. The current study investigates sensitivity of direct numerical simulation (DNS) of such a flow to computational parameters. In particular, effects of the computational domain dimensions, grid refinement, thickness of the splitter plate, and the laminar boundary layer characteristics at the splitter plate trailing edge are considered. Flow conditions used in DNS are close to those from the experiments by Bell & Mehta (1990), where untripped boundary layers co-flowing on both sides of a splitter plate mix downstream of the plate. No artificial perturbations are used in simulations to trigger the flow transition to turbulence. DNS were conducted using the spectral-element method implemented in the open-source code Nek5000. Mean flow statistics are presented for the spatially developing self-similar flow, including high-order velocity moments. Such statistics will be used for validation of high-order Reynolds-Averaged Navier-Stokes (RANS) closure models.

Keywords

turbulence, shear layer, numerical simulation, Gram-Charlier

Degree Name

Mechanical Engineering

Level of Degree

Doctoral

Department Name

Mechanical Engineering

First Committee Member (Chair)

Svetlana V. Poroseva

Second Committee Member

Peter Vorobieff

Third Committee Member

C. Randall Truman

Fourth Committee Member

Edl Schamiloglu

Document Type

Dissertation

Language

English

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