Aeronautic systems
http://hdl.handle.net/10204/907
20170711T10:30:07Z

Modelling flow phenomena in time dependent store release from transonic aircraft
http://hdl.handle.net/10204/9200
Modelling flow phenomena in time dependent store release from transonic aircraft
MacLucas, David A; Gledhill, Igle MA
Computational Fluid Dynamics is routinely used in clearance of stores for carriage and release from aircraft in the transonic range of flight. A wellknown validation case is modelled in this study, for which aerodynamic loads have been compared with wind tunnel experimental data by other authors. In this study, having validated the numerical model, we apply more recent methodologies from flow dynamics to study the detailed flow field in the region of the store fins.
59th Annual conference of the South African Institute of Physics, Johannesburg, 711 July 2014
20140701T00:00:00Z

Theoretical treatment of fluid flow for accelerating bodies
http://hdl.handle.net/10204/9040
Theoretical treatment of fluid flow for accelerating bodies
Gledhill, Irvy MA; Roohani, H; Forsberg, K; Eliasson, P; Skews, BW; Nordström, J
Most computational fluid dynamics simulations are, at present, performed in a bodyfixed frame, for aeronautical purposes. With the advent of sharp manoeuvre, which may lead to transient effects originating in the acceleration of the centre of mass, there is a need to have a consistent formulation of the NavierStokes equations in an arbitrarily moving frame. These expressions should be in a form that allows terms to be transformed between noninertial and inertial frames, and includes gravity, viscous terms, and linear and angular acceleration. Since no effects of body acceleration appear in the inertial frame NavierStokes equations themselves, but only in their boundary conditions, it is useful to investigate acceleration source terms in the noninertial frame. In this paper, a derivation of the energy equation is provided in addition to the continuity and momentum equations previously published. Relevant dimensionless constants are derived which can be used to obtain an indication of the relative significance of acceleration effects. The necessity for using Computational Fluid Dynamics to capture nonlinear effects remains and various implementation schemes for accelerating bodies are discussed. This theoretical treatment is intended to provide a foundation for interpretation of aerodynamic effects observed in manoeuvre, particularly for accelerating missiles.
© SpringerVerlag Berlin Heidelberg 2016. This is a postprint version of the article. The definitive published version can be obtained from http://link.springer.com/article/10.1007/s0016201603820
20160201T00:00:00Z

Acceleration parameters for fluid physics with accelerating bodies
http://hdl.handle.net/10204/8952
Acceleration parameters for fluid physics with accelerating bodies
Gledhill, Irvy MA; Roohani, H; Biobaku, A; Skews, B
Theoretical work on transforming the NavierStokes equations into arbitrarily accelerating frames has included the continuity, momentum, and energy conservation equations. An analysis of the momentum equation in nondimensional terms leads to an acceleration parameter that appears to be new in fluid physics, but is known in cosmology. A selection of cases for rectilinear acceleration has been chosen to illustrate the point that this parameter alone does not govern regimes of flow about significantly accelerating bodies, and reference must be made, above all, to the Mach number for transonic effects. Other parameters from the literature on impulsive startup in wind tunnels are also shown to be useful in delimiting regimes of flow, such as the Freymuth startup time. Two dominant effects in fluid dynamics with accelerating objects are shown to be flow history, a term being used to cover the difference between an instantaneous flow field with an accelerating body and the flow field about the same body at steady state, and the dependence of stagnation pressure on acceleration. The dependence of these effects on dimensionless parameters is explored.
The Proceedings of The 60th Annual Conference of The South African Institute of Physics (SAIP2015), 29 June  3 July 2015, Port Elizabeth, Boardwalk Convention Centre
20160601T00:00:00Z

Improving the workplace environment
http://hdl.handle.net/10204/8868
Improving the workplace environment
Gledhill, Irvy MA; Butcher, G
Research has shown that companies with more diversity and a better workplace perform better. So what makes a good workplace in physics, where women and men can work to their full potential? In the Improving the Workplace Environment workshop of the 5th IUPAP International Conference on Women in Physics, participants heard about initiatives taking place in Canada, the UK, Japan, and India to improve the workplace environment and shared good practices from around the world. Some of the less tangible aspects of the workplace environment, such as unconscious bias and accumulation of advantage and disadvantage, were explored.
Proceedings of the Fifth IUPAP International Conference on Women in Physics, 58 August 2014, Waterloo, Canada
20140801T00:00:00Z