Wave drag due to lift for transonic airplanes

Lift dominated pointed aircraft configurations are considered in the transonic range. These are treated as lifting wings of zero thickness with an aspect ratio of order one. An inner expansion which starts as Jones' theory is matched to a nonlinear outer transonic theory as in Barnwell's earlier work. Expressions for the wave drag due to the equivalent body are derived. Some examples of numerical calculations for different configurations are presented

Shocks in asymmetric simple exclusion processes of interacting particles

In this paper, we study shocks and related transitions in asymmetric simple exclusion processes of particles with nearest neighbor interactions. We consider two kinds of inter-particle interactions. In one case, the particle-hole symmetry is broken due to the interaction. In the other case, particles have an effective repulsion due to which the particle-current-density drops down near the half filling. These interacting particles move on a one dimensional lattice which is open at both the ends with injection of particles at one end and withdrawal of particles at the other. In addition to this, there are possibilities of attachments or detachments of particles to or from the lattice with certain rates. The hydrodynamic equation that involves the exact particle current-density of the particle conserving system and additional terms taking care of the attachment-detachment kinetics is studied using the techniques of boundary layer analysis.Comment: 10 pages, 8 figure

Similarity solution for cylindrical magnetohydrodynamic blast waves

A similarity solution is obtained for the flow behind a very strong (in the hydrodynamic sense) cylindrical magnetohydrodynamic shock wave produced by the sudden release of energy along a line of infinite extent in a plasma. The plasma is assumed to be an ideal gas with infinite electrical conductivity, and to be permeated by the azimuthal magnetic field of a line current. It is shown that it is of critical importance to take into account the ambient magnetic pressure, no matter how small. It is found that, to preserve similarity, the external circuit is required to maintain a constant axial current; this result also appears in the related problem, treated by Greenspan, where the ambient plasma is nonconducting. This boundary condition is shown to have some interesting consequences, especially with regard to the energy content of the system. The dependence of the shock speed on the explosive energy is determined as a function of the ambient magnetic field both for the present case and for Greenspan's case, and interesting differences are noted. Other differences between the two cases are also discussed

Bulk and surface transitions in asymmetric simple exclusion process: Impact on boundary layers

In this paper, we study boundary-induced phase transitions in a particle non-conserving asymmetric simple exclusion process with open boundaries. Using boundary layer analysis, we show that the key signatures of various bulk phase transitions are present in the boundary layers of the density profiles. In addition, we also find possibilities of surface transitions in the low- and high- density phases. The surface transition in the low-density phase provides a more complete description of the non-equilibrium critical point found in this system.Comment: 9 pages including figure

Problems in the Theory of Viscous Compressible Fluids

The present study was suggested by several problems and difficulties that had appeared in previous experimental and theoretical investigations of viscosity effects in compressible fluids. The outstanding problem was the extension of the classical (Prandtl) boundary-layer theory to high-speed flow, especially supersonic flow. In the boundary-layer theory the equations of motion are simplified by assuming that viscous effects are confined to a narrow region close by the wall through which changes are rapid compared to those in the direction of the wall. Then the resulting non-linear equations are studied with the aim of obtaining the flow field in this narrow region or boundary layer. The pressure is usually obtained from the potential or no-viscous flow about the body. Several authors have studied a boundary-layer theory which has the same basic assumptions but which allows for compressibility and heat conduction. However, in supersonic flow several phenomena are known which show that the basic assumptions of boundary-layer theory do not apply, at least in certain regions

The Winter Camp of the Viking Great Army, AD 872–3, Torksey, Lincolnshire

This paper presents the results of a multidisciplinary project that has revealed the location, extent and character of the winter camp of the Viking Great Army at Torksey, Lincolnshire, of AD 872–3. The camp lay within a naturally defended area of higher ground, partially surrounded by marshes and bordered by the River Trent on its western side. It is considerably larger than the Viking camp of 873–4 previously excavated at Repton, Derbyshire, and lacks the earthwork defences identified there. Several thousand individuals overwintered in the camp, including warriors, craftworkers and merchants. An exceptionally large and rich metalwork assemblage was deposited during the Great Army’s overwintering, and metal processing and trading was undertaken. There is no evidence for a pre-existing Anglo-Saxon trading site here; the site appears to have been chosen for its strategic location and its access to resources. In the wake of the overwintering, Torksey developed as an important Anglo-Saxon borough with a major wheel-thrown pottery industry and multiple churches and cemeteries. The Torksey evidence allows for a radical reappraisal of the character of Viking winter camps, and the legacy of the Viking Great Army for Anglo-Saxon England