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Dr Ying H Huang


Postgraduate Research Student
+44 (0)1483 683024
17 AA 04

Academic and research departments

Department of Mathematics.

My publications

Publications

Huang Y, Turner M (2017) Dynamic fluid sloshing in a one-dimensional array of coupled vessels.,Physical Review Fluids2(12)124801 American Physical Society
This paper investigates the coupled motion between the dynamics of N vessels coupled together in a one-dimensional array by springs, and the motion of the inviscid fluid sloshing within each vessel. We develop a fully-nonlinear model for the system relative to a moving frame such that the fluid in each vessel is governed by the Euler equations and the motion of each vessel is modelled by a forced spring equation. By considering a linearization of the model, the characteristic equation for the natural frequencies of the system is derived, and analysed for a variety of non-dimensional parameter regimes. It is found that the problem can exhibit a variety of resonance situations from the 1 : 1 resonance to (N + 1)-fold 1 : · · · : 1 resonance, as well as more general r : s : · · · : t resonances for natural numbers r, s, t. This paper focuses in particular on determining the existence of regions of parameter space where the (N + 1)-fold 1 : · · · : 1 resonance can be found.
Aston P, Christie M, Huang Y, Nandi M (2018) Beyond HRV: attractor reconstruction using the entire cardiovascular waveform data for novel feature extraction,Physiological Measurement39(2)024001 IOP Publishing
Advances in monitoring technology allow blood pressure waveforms to be collected at sampling frequencies of 250-1000Hz for long time periods. However, much of the raw data are under analysed. Heart rate variability (HRV) methods, in which beat-to-beat interval lengths are extracted and analysed, have been extensively studied, However, this approach discards the majority of the raw data. Objective: Our aim is to detect changes in the shape of the waveform in long streams of blood pressure data. Approach: Our approach involves extracting key features from large complex datasets by generating a reconstructed attractor in a three-dimensional phase space using delay coordinates from a window of the entire raw waveform data. The naturally occurring baseline variation is removed by projecting the attractor onto a plane from which new quantitative measures are obtained. The time window is moved through the data to give a collection of signals which relate to various aspects of the waveform shape. Main results: This approach enables visualisation and quantification of changes in the waveform shape and has been applied to blood pressure data collected from conscious unrestrained mice and to human blood pressure data. The interpretation of the attractor measures is aided by the analysis of simple artificial waveforms. Significance: We have developed and analysed a new method for analysing blood pressure data that uses all of the waveform data and hence can detect changes in the waveform shape that HRV methods cannot, which is confirmed with an example, and hence our method goes "beyond HRV".
Ardakani H. Alemi, Bridges T.J., Gay-Balmaz F., Huang Y.H., Tronci C. (2019) A variational principle for fluid sloshing with vorticity, dynamically coupled to vessel motion,Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences Royal Society
A variational principle is derived for two-dimensional incompressible rotational fluid flow with a free surface in a moving vessel when both the vessel and fluid motion are to be determined. The fluid is represented by a stream function and the vessel motion is represented by a path in the planar Euclidean group. Novelties in the formulation include how the pressure boundary condition is treated, the introduction of a stream function into the Euler- Poincaré variations, the derivation of free surface variations, and how the equations for the vessel path in the Euclidean group, coupled to the fluid motion, are generated automatically.
In this thesis we investigate the dynamics of coupled liquid sloshing systems, which consist of a one-dimensional array of vessels, partially filled with fluid, being connected together by nonlinear springs. The fluid motion induces a hydrodynamic force on the side walls of the vessel, which induces the vessel to move. The vessel movement is also controlled via a restoring force of the attached springs, which in turn causes the fluid to alter its motion. The simplest coupled liquid sloshing system consists of one vessel connected to a side wall via a spring. We review this example and investigate the techniques documented in the literature to study the linear problem of such a system. Then we extend this linear theory to multivessel systems, in particular focussing on the 2-vessel system which introduces the notion of modes being in-phase or out-of-phase with each other. In the general N-vessel system we also identify the existence in parameter space of internal resonances, where different modes oscillates at the same frequency. Such a resonance provides a mechanism for energy exchange between modes in the nonlinear system. The nonlinear dynamics of the coupled liquid sloshing system are studied by employing a symplectic integration scheme based on a variational principle, to the shallow-water form of the governing equations. We present results for the shallow-water scheme in the linear, weakly nonlinear and fully nonlinear regimes. The shallow-water numerical scheme has trouble dealing with breaking waves, so we perform a feasibility study where we attempt to use a similar approach for a non-shallow fluid system. The governing equations are derived and results presented in the linear amplitude regime for the 1-vessel system. Finally, we develop variational principles for the coupled liquid sloshing system in the Eulerian framework based on the principle of constrained variations to derive the governing fluid equations and free-surface boundary conditions, from a natural Lagrangian functional. We use this constrained variational approach to derive the fully rotational 2D Euler equations and its stream function formulation.