Postgraduate Fluid Mechanics Seminars Autumn 2019

These seminars (unless otherwise stated) will take place on Wednesdays at 4pm in room 707 on a bi-weekly basis - see the map for further details.

23 October 2019

Speaker: Jurriaan Gillissen (UCL)

Title: Shear Thickening in Dense Suspensions

Abstract:
I will present a tensorial constitutive model for the microstructure and stress in shear thickening suspensions. The model is applied to time varying flows (oscillatory shear and abrupt shear reversal).

06 November 2019

NO SEMINAR

13 November 2019 in Room 505

Speaker: Lois Baker (Imperial College London)

Title: Superharmonics of Internal Tides in Non-Uniform Stratification

Abstract:

Internal tides are internal gravity waves that are generated in the stratified ocean when the tide sloshes over rough seafloor topography. The mechanism by which energy cascades from the large scale internal tides to smaller scales where mixing and dissipation can act is of great importance in understanding energy pathways in the ocean and correctly parametrising climate models, but remains an open question. Here, the excitation of near-resonant superharmonics are investigated for their possible role in extracting energy from the mode-1 internal tide.

20 November 2019 in Room 505

Speaker: Elle McLean (UCL)

Title: Using series truncation and collocation to investigate supercritical spillway flows

Abstract:
Assuming a fluid is inviscid and incompressible, and the flow is steady, two-dimensional and irrotational, it follows that through potential flow theory we can use conformal mappings to investigate the behaviour of the flow. This can lead to analytic solutions. For this to be the case, gravity is ignored, leading to what are known as free-streamline solutions. However, if we include the effects of gravity, we can use conformal mappings, supplemented by a numerical method, to obtain a numerical solution. In this talk, I will present a method used by Vanden-Broeck to find the free surface of a supercritical spillway flow. Results will also be discussed for similar problems for which the same method can be employed.

27 November 2019 in Room 505

Speaker: Edward Goldsmith (UCL)

Title: The Shallow Water Equations over large amplitude topography

Abstract:
In this talk we consider the rotating shallow water equations over small-scale topography. By using multi-scale methods to derive a “homogenized” form of the RSWE, we are able to capture the interaction of a large-scale, propagating wave with a range of topographic profiles, including periodically spaced sea-mounts, randomly spaced seamounts, and non-uniformly spaced hills with randomly distributed radii and height. This builds on previous work by fluid-dynamicists who have done similar analysis in the quasi-geostrophic limit, as it allows us to consider large-amplitude topography (including islands), the topographic response of Rossby AND Gravity waves, and also permits analysis over all regions of Earth’s oceans, rather than just the mid-latitudes.