Entrainment in turbulent round jets

Turbulent jets of gas or liquid play a crucial role in combustion of fossil fuels, the delivery of aerosols to the human airway and lungs and various industrial applications. One of the main features of a turbulent jet is that as it evolves from its point of origin it engulfs fluid from its surroundings. This entrainment enables the jet boundaries to spread. The turbulent entrainment process and the mechanisms that control the transport of mass, momentum, and scalars from a turbulent region of a fluid to a non-turbulent region are of widespread interest in science and engineering. Despite decades of research on turbulent flows, there still remain open questions regarding the entrainment mechanisms and as to whether small-scale or large-scale turbulent motions are dominant in the entrainment process. We propose to address this issue by comparing entrainment in jets emanated from origins with different boundary conditions created by placing different control rings at the jet exit nozzles. Accurate optical velocity and concentration measurements will reveal the entrainment coefficient and various length scales in different nozzle cases allowing for discovering a direct link between scales of motion and entrainment in turbulent jets.

Faculty Supervisor:

Andrew Pollard

Student:

Partner:

Norwegian University of Science and Technology

Discipline:

Engineering

Sector:

Education

University:

Queen's University

Program: