Master of Engineering Science
Mechanical and Materials Engineering
This thesis presents the analysis of the effects of three-dimensional grooves on the flow responses in laminar channel flows. The wall topographies were expressed using the two-dimensional Fourier expansions. A spectrally accurate algorithm based on the Immersed Boundary Conditions (IBC) was used to determine the solution for the field equations and extract information about the velocity and pressure fields. The effects of grooves on the pressure losses were assessed by determining the additional pressure gradient required to maintain the same flow rate through the grooved channel as through the reference smooth channel. Effects of groove wave numbers, groove amplitudes, the relative position of the upper and lower groove systems as well as the flow Reynolds number were considered. It has been shown that it is possible to identify surface topographies that lead to the reduction of pressure losses in spite of an increase of the wetted surface area. Only topographies that show a preference for the longitudinal wave numbers are able to reduce pressure losses. The interaction of groove systems present on different channel walls affects the magnitude of drag reduction. The most effective relative positions of these systems have been identified.
Wang, Yanbei, "Effects of Grooves on Drag in Laminar Channel Flow" (2018). Electronic Thesis and Dissertation Repository. 5487.