Postgraduate Seminars

These seminars (unless otherwise stated) will take place on Thursdays at 2pm-3pm on an almost weekly basis.

Autumn 2024

Talks are being given by 2nd and 3rd year Mathematics PhD students for PhD students.

26 September 2024 in 25 Gordon Street - Room 416

Speaker: Luke Debono

TITLE: an introduction to molecular modelling of complex fluids in rheology

Abstract:   
In this seminar, I will introduce the field of rheology with some fundamental concepts supported by real world examples of complex fluids.  We will then consider molecular simulation as a tool for conducting microscale experiments on different molecular models of complex fluids. Finally, I will introduce my own modelling approach followed by some results from the past year.

03 October 2024 in 25 Gordon Street - Room 416

Speaker: Xinyu Yao

TITLE: free surface flow past a high-speed submerged hydrofoil

Abstract:   
In this seminar, I will introduce, in the limit of large Froude number, a closed-form, numerical solution of spectral method for steady, two-dimensional, inviscid, free-surface attached flow over a submerged planar hydrofoil for arbitrary angles of attack and depths of submergence. The doubly connected flow domain is conformally mapped to a concentric annulus in an auxiliary plane. The complex flow potential and its derivative, the complex velocity, are obtained in the auxiliary plane by considering their form at known special points in the flow, and the required conformal mapping is determined by explicit integration. Finally, three real solution parameters of the conformal mapping will be determined as the simultaneous roots of three nonlinear algebraic equations arising from the flow normalization through Newton's iteration. The numerical solution format enables precise evaluation of various flow quantities, including the lift on the foil, in relation to physical parameters.

10 October 2024 in 25 Gordon Street - Room 416

Speaker: Courteney Hirst

TITLE: Erosion of surfaces by trapped vortices

Abstract:   
Two two-dimensional free boundary problems describing the erosion of solid surfaces by the flow of inviscid fluid in the presence of trapped vortices are considered. The first problem tackles an initially flat, infinite fluid-solid interface with uniform flow at infinity and a vortex in equilibrium above the surface. The second involves flow around a finite body with a trailing Föppl-type vortex pair. The conformal invariance of the complex potential permits both problems to be formulated as a Polubarinova-Galin (PG) type equation in which the time-dependent eroding surface in the physical plane is mapped to the fixed boundary of the unit disk. The Hamiltonian governing the equilibrium position of the vortex (or vortex pair in the second problem) is also found from the same map. In each problem the PG equation giving the conformal map is found numerically and the time-dependent evolution of the interface and vortex location determined. Different models governing the erosion of the interface are investigated in which the normal velocity of the boundary depends on some given function of the fluid flow velocity at the boundary. Typically, in the infinite surface case, erosion leads to the formation of a symmetric valley beneath the vortex which, in turn, moves downward toward the interface. A finite body undergoes erosion which is asymmetric in the flow direction leading to a flattening of the lee surface of the body so displaying some similarity to experiments and associated viscous theory.

17 October 2024 in 25 Gordon Street - Room 416

Speaker: Dhruva Pamulaparthy

TITLE: Do elephants dream of electric sheep? - large deviations in nonequilibrium systems with memory

Abstract:   
This talk is an introduction (with minimum maths!) to the type of problems that I currently work on. We will examine memory-dependence in nonequilibrium systems through simple toy examples, building to processes that never forget such as “elephant” random walks. Systems with memory are routinely encountered in physics (spin-glasses), biology (active-matter), engineering (transportation) and mathematics (probability theory). We are particularly interested in statistical properties of quantities such as currents which in general are characterized by large deviations describing rare-events and fluctuations. However, we will find that memory complicates large-deviation calculations and advanced computational methods such as machine learning become necessary.

24 October 2024

Speaker: TBC

TITLE: TBC

Abstract:   
TBC

31 October 2024

Speaker: TBC

TITLE: TBC

Abstract:   
TBC

07 November 2024

Speaker: TBC

TITLE: TBC

Abstract:   
TBC

14 November 2024

Speaker: TBC

TITLE: TBC

Abstract:   
TBC

21 November 2024

Speaker: TBC

TITLE: TBC

Abstract:   
TBC

28 November 2024

Speaker: TBC

TITLE: TBC

Abstract:   
TBC

05 December 2024

Speaker: TBC

TITLE: TBC

Abstract:   
TBC

12 December 2024

Speaker: TBC

TITLE: TBC

Abstract:   
TBC