On the instability of hypersonic flow past a wedge

The instability of a compressible flow past a wedge is investigated in the hypersonic limit. Particular attention is given to the Tollmien-Schlichting waves governed by triple-deck theory though some discussion of inviscid modes is given. It is shown that the attached shock has a significant effect on the growth rates of Tollmien-Schlichting waves. Moreover, the presence of the shock allows for more than one unstable Tollmien-Schlichting wave. Indeed, an infinite discrete spectrum of unstable waves is induced by the shock, but these modes are unstable over relatively small but high frequency ranges. The shock is shown to have little effect on the inviscid modes considered by previous authors and an asymptotic description of inviscid modes in the hypersonic limit is given

What makes a Tory MP rebel: and what are their red lines on Brexit?

The Conservatives now depend on the Democratic Unionist Party to push through legislation in the Commons - but can Theresa May even rely on her own MPs to back her on Brexit? Philip Cowley looks at the factors that prompt MPs to rebel and what we know about the views of Tory MPs. He finds there will be plenty of scope for rebellion

On the instability of hypersonic flow past a flat plate

The instability of hypersonic boundary-layer flows over flat plates is considered. The viscosity of the fluid is taken to be governed by Sutherland's law, which gives a much more accurate representation of the temperature dependence of fluid viscosity at hypersonic speeds than Chapman's approximate linear law; although at lower speeds the temperature variation of the mean state is less pronounced so that the Chapman law can be used with some confidence. Attention is focussed on the so-called (vorticity) mode of instability of the viscous hypersonic boundary layer. This is thought to be the fastest growing inviscid disturbance at hypersonic speeds; it is also believed to have an asymptotically larger growth rate than any viscous or centrifugal instability. As a starting point the instability of the hypersonic boundary layer which exists far downstream from the leading edge of the plate is investigated. In this regime the shock that is attached to the leading edge of the plate plays no role, so that the basic boundary layer is non-interactive. It is shown that the vorticity mode of instability of this flow operates on a significantly different lengthscale than that obtained if a Chapman viscosity law is assumed. In particular, it is found that the growth rate predicted by a linear viscosity law overestimates the size of the growth rate by O(M(exp 2). Next, the development of the vorticity mode as the wavenumber decreases is described, and it is shown that acoustic modes emerge when the wavenumber has decreased from it's O(1) initial value to O(M (exp -3/2). Finally, the inviscid instability of the boundary layer near the leading edge in the interaction zone is discussed and particular attention is focussed on the strong interaction region which occurs sufficiently close to the leading edge. It is found that the vorticity mode in this regime is again unstable, and that it is concentrated in the transition layer at the edge of the boundary layer where the temperature adjusts from its large, O(M(exp 2), value in the viscous boundary layer, to its O(1) free stream value. The existence of the shock indirectly, but significantly, influences the instability problem by modifying the basic flow structure in this layer

Trends in region-based localism among MPs: 2010-2019

Voters typically want their elected representatives to have roots in their local area, yet a large number of British MPs lack close ties with their constituency. Drawing on new research, Rob Gandy, Philip Cowley and Scott Foster illustrate trends in localism among MPs between the 2010 and 2019 general elections

Speaking for Britain? MPs broadly reflect the views of their supporters on Europe – but one side should worry a little more than the other

Do MPs’ views on Europe reflect those of their voters? Tim Bale (left), Sofia Vasilopoulou, Philip Cowley and Anand Menon asked both groups the same questions about the EU, and found some notable differences on the issues of freedom of movement and migrant benefits. In particular, Labour voters are significantly more Eurosceptic than the MPs they elect

Expert voices: is it time to lower the voting age to 16?

The question of whether the UK should lower the minimum voting age from 18 to 16 has been on the agenda recently, with Ed Miliband making it explicit Labour policy, and the SNP enfranchising 16 and 17 year olds to good effect during the Scottish independence referendum. As part of the LSE’s ‘Expert Voices’ series, Public Policy Group Digital Editor Cheryl Brumley commissioned Sarah Birch, Richard Berry, Philip Cowley, and Andrew Mycock to record a short monologue about their thoughts on the issue, and to answer the question ‘is it time for the UK to lower the voting age to 16?

Parental status as an electoral asset: how voters view politicians with and without children

Philip Cowley and Rosie Campbell examine the public's view of British politicians with and without children, as well as the behaviour of MPs in their communications with voters. They find a preference for candidates who are parents and no punishment effect for women politicians with children

Design for electric light and power plant

Thesis (B.S.)--University of Illinois, 1902.Typescript

Legislator dissent as a valence signal

Existing research suggests that voters tend to respond positively to legislator independence due to two types of mechanism. First, dissent has an indirect effect, increasing a legislator’s media coverage and personal recognition among constituents (profile effects). Second, constituents react positively to dissent when this signals that the legislator has matching political or representational preferences (conditional evaluation). We argue for a third effect: dissent acts as a valence signal of integrity and trustworthiness. Consistent with the valence signalling mechanism, we use new observational and experimental evidence to show that British voters have a strong and largely unconditional preference for legislators who dissent. Our findings pose a dilemma for political systems which rely on strong and cohesive parties

Votes at 16: democracy experts respond to Ed Miliband’s proposal

Ed Miliband used his speech to the Labour Party conference this week to announce his support for lowering the voting age to 16 for all UK elections. This follows the decision to allow 16- and 17-year-olds to vote in the Scottish independence referendum. In this post, Democratic Audit asks leading experts and practitioners to respond to Miliband’s proposal