The veins in the Drosophila wing have a characteristic width, which is regulated by the activity of the Notch pathway. The expression of the Notch-ligand Delta is restricted to the developing veins, and coincides with places where Notch transcription is lower. We find that this asymmetrical distribution of ligand and receptor leads to activation of Notch on both sides of each vein within a terr...

The product of the Drosophila gene Serrate acts as a short-range signal during wing development to induce the organising centre at the dorsal/ventral compartment boundary, from which growth and patterning of the wing is controlled. Regulatory elements reflecting the early Serrate expression in the dorsal compartment of the wing disc have recently been confined to a genomic fragment in the 5'-up...

The state-space representation of an aerodynamic vortex lattice model is considered from a classical and system identification perspective. Using an aerodynamic vortex model as a numerical simulator of a wing tunnel experiment, both full state and limited state data or measurements are considered. Two possible approaches for system identification are presented and modal controllability and obse...

Slender-body theory is used to calculate the lift and drag forces acting on a thin slender delta wing cambered to form part of the surface of a circular cone, in the type of flow in which separation is from the trailing edge only. The boundary condition satisfied by the flow on the wing surface is applied there, instead of on a nearby plane as is usual in linearized theory. This has relatively ...

Rotating blades on helicopters experience reverse flow under high advance ratio conditions. Here, reverse flow is characterized by the flow traveling from the sharp trailing edge to the blunt leading edge. Uncertainty in the blade aerodynamic loads under these conditions has been a limitation during the design of high-speed rotorcraft. In this work, we hypothesize that the reverse flow over a y...

An experimental investigation was performed with two aims: (1) to clarify the existence of the dual leading-edge vortices (i.e. two vortices with the same sense of rotation located close to the leading edge above the leeward wing surface) observed on flapping wings in previous studies; (2) to study systematically the influences of kinematic and geometric parameters on such a vortical structure....

An assessment of unstructured grids for use in Detached-Eddy Simulation (and more generally in Large-Eddy Simulation) of massively separated ows is presented. The role of the grid, its generation and re nement, are considered via calculation of three high-Reynolds number turbulent ows of aerodynamic interest: the massively separated ow over a forebody in cross ow, the ow over a delta wing at 27...