A trajectory control problem for simple micro air vehicles (MAVs) is introduced and studied. The MAVs are endowed with the ability to estimate their position and velocity and can control their drag coefficient. The objective of this work is to design a control law for the drag coefficient in order to land the MAV close to a desired streamwise location, after being dropped from an airborne carri...

The following research paper presents an up-to-date status of the testing of a Dual-Mode Scramjet (DMSJ) model which is experimentally operated at UVa’s Aerospace Research Laboratory. The optical technique Stereoscopic Particle Image Velocimetry (SPIV) is applied to the combustor of the DMSJ with a ramp fuel injector configuration. SPIV is utilized to measure the three-dimensional, combusting, ...

Utilizing experimental techniques of Nano-particle based Planar Laser Scattering (NPLS) and schlieren photography, the flow patterns and mixing characteristics of a designed HYLTE (HYpersonic Low TEmperature) nozzle were investigated in this paper. In order to visualize the non-reacting flowfield of supersonic angled jets into a supersonic crossflow in the HYLTE nozzle, a testing section with w...

Abstract: In this paper, a comparison between h ig h e r order schemes has been performed in terms of numerical accuracy. Four finite difference schemes, the e xp lic it fourth-order compact Pade scheme, the implicit fourth-order Pade scheme, flowfield dependent variation (FDV) meth o d a n d h igh order compact flowfie ld dependent variation (HOC-FDV) scheme are tes ted. The FDV scheme is used...

This paper presents a computational study on the aerodynamic effectiveness of vane-type fan-flow deflectors used for reducing jet noise from a supersonic turbofan exhaust with bypass ratio of 2.7. The numerical code solved the three-dimensional Reynolds-averaged Navier–Stokes equations. A series of nozzle configurations using deflector vanes of variable number, airfoil section, azimuthal mounti...

A hybrid particle scheme is presented for the simulation of compressible gas flows involving both continuum regions and rarefied regions with strong translational nonequilibrium. The direct simulation Monte Carlo (DSMC) method is applied in rarefied regions, while remaining portions of the flowfield are simulated using a DSMC-based low diffusion particle method for inviscid flow simulation. The...

The flow solver, UBIFLOW, was developed with the goal of producing efficient, accurate flow solution software capable of handling complex configurations. In the work presented here, UBIFLOW’s ability to simulate the flowfield of complex configurations was tested on a couple of launch vehicles. The predictive capability of UBIFLOW was demonstrated through the use of sample launch configurations ...

A theoretical analysis of three–dimensional cavitating flows based on a boundary element approach which includes rotational and viscous flow effects is presented. Partial sheet cavitation is studied by a closed–cavity nonlinear model which includes the prediction of the cavity detachment point. The trailing vorticity path is described by a wake– alignment technique. Viscosity effects are includ...

A hybrid particle scheme, which is based on the direct simulation Monte Carlo (DSMC) method and incorporates a low diffusion particle method for continuum flow simulation, is extended for improved efficiency and wider applicability. The hybrid scheme is intended for simulation of gas flows involving a wide range of Knudsen number regimes, where strong coupling is desired between calculations in...

Infrared Thermography (IT) is an imaging technology aimed at the non-invasive measurement of the temperature distribution of the observed object. The capability to capture the temperature map of an object by an imaging device, makes IT an effective solution within Wind Tunnels systems, because it avoids the undesired drawbacks which are typically raised by intrusive diagnostics, like the altera...