This research aims to measure four-dimensional, spatio-temporal velocity fields in unsteady periodic flows, such as those around rotorcraft. Periodic planar velocity fields at several slices of the flowfield are used to compute the component normal to the planes. The flow being incompressible, satisfying the continuity equation is sufficient. The velocity field reconstruction technique is valid...

Laminar separation and subsequent transition to turbulent flow plays an important role in the performance of airfoils operating at low Reynolds number (Re<10). For better understanding of the formation and turbulent breakdown of laminar separation bubbles (LSB), both local and two-dimensional global linear stability analysis are applied to investigate the stability of a CFD time-averaged non-pa...

A Dynamic Data Driven Application Systems (DDDAS) methodology is developed for evaluation of fluid-thermal systems wherein a complete specification of the boundary conditions is not known a priori and experimental diagnostics are restricted to a limited region of the flowfield. The Closed Loop formulation of DDDAS is used whereby experiment and simulation are synergized in an iterative manner t...

Regurgitation in the heart diastolic phase represents a critical flow condition associated with many heart valve design considerations. The finite volume method, the Low-Reynolds-Number k-ω turbulent model and sliding mesh model are employed to solve and compare the complex flow field and the torque in each case. The end results expected from a cardiovascular CFD analysis are not limited only t...

bhw = half width of the line broadening, Å Eabs = integrated absorption energy,W=cm Eabs;p = absorption energy per particle, W Eemis = integrated emission energy,W=cm Eemis;p = emission energy per particle, W Eray = energy of a ray, photon bundle, W Fnum = Number of particles represented by a simulated particle i = cell index in the x direction j = cell index in the r direction k = line index k...

Field experimental observations from GPS Radiosonde, 3 meteorological towers and 16 automated weather stations were employed to validate boundary layer wind field simulations made with Weather Research and Forecasting (ARW) model in the tropical coastal Kalpakkam region in southern India during the Round Robin Exercise (RRE) field experiment period (14 -24 September 2010). Three nested domain w...

We report a laser diagnostic technique which relies on planar laser-induced fluorescence of vibrationally excited nitric oxide (NOv 1) molecules produced from the 355 nm photodissociation of seeded NO2 for molecular tagging velocimetry applications. The technique was applied toward an axisymmetric highly underexpanded jet flowfield to yield single-component (streamwise) velocity maps. Detection...

Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow over a cylinder are presented for axial- and transverse-oriented dipoles with different strengths. ANSYS CFX is used to carry out calculations for steady, laminar flows at a Mach number of 6.1, with a model for electrical conductivity as a function of temperature and pressure. The low magnetic Reynolds number (<<1) calculated ba...

A large-eddy simulation (LES) solver which combines an immersed-boundary technique with a curvilinear structured grid has been developed to study the temporal and spatial dynamics of an incompressible rotor tip-clearance flow. The overall objective of these simulations is to determine the underlying mechanisms for low-pressure fluctuations downstream of the rotor near the endwall. Salient featu...