Turbulent mixed convection of a nanofluid (water/Al2O3, Φ=.02) has been studied numerically. Two-phase mixture model has been used to investigate the effects of nanoparticles mean diameter on the flow parameters. Nanoparticles distribution at the tube cross section shows that the particles are uniformly dispersed. The non-uniformity of the particles distribution occurs in the case of large nano...

A pressure-based implicit procedure to solve the Euler and Navier-Stokes equations on a nonorthogonal mesh with collocated finite volume formulation is described. The boundedness criteria for this procedure are determined from Normalized Variable diagram (NVD) scheme.The procedure incorporates the ε−k eddy-viscosity turbulence model. The algorithm is tested for inviscid and turbulent transonic ...

Radiation transport plays important roles in stellar atmospheres, but the effects of turbulence are being obscured by other such as stratification. Using radiative hydrodynamic simulations forced turbulence, we determine decay rates sinusoidal large-scale temperature perturbations different wavenumbers optically thick and thin regimes. Increasing wavenumber increases rate both regimes, this eff...

Various classic icing codes have been developed and used by the aircraft manufacturers to predict the ice shapes evolution. These codes apply boundary layer integral analysis, based on sand grain roughness, to estimate the convective heat transfer coefficient around the iced airfoil and adopt abrupt transition between laminar and turbulent flow. In the present work, the integral analysis is als...

We consider the interaction of free-stream disturbances with the leading edge of a body and its effect on the transition point. We present a method which combines an asymptotic receptivity approach, and a numerical method which marches through the Orr-Sommerfeld region. The asymptotic receptivity analysis produces a three deck eigensolution which in its far downstream limiting form, produces an...

Stochastic versions of stability equations are developed in order to develop integrated models of transition and turbulence and to understand the effects of uncertain initial conditions on disturbance growth. Stochastic forms of the resonant triad equations, a high Reynolds number asymptotic theory, and the parabolized stability equations are developed.

Wall-modeled large-eddy simulation is applied to a transonic axial compressor rotor (NASA Rotor 37). The simulation results show a significant improvement over fully turbulent RANS in the prediction of the overall performance, mainly by capturing boundary layer transition on the blade. Sensitivity of the result to the end-wall boundary conditions (isothermal/adiabatic walls) and the inflow prof...

After studying the performance and characteristics of actual laminar flowmeters a new disposition for this type of sensors is proposed in such a way that the measurement errors introduced by the intrinsic nature of the device can be minimized. The preliminary study shows that the developing entry region introduces non-linearity effects in all these devices. These effects bring about not only er...

We consider vertical heat transport in Keplerian accretion disks, including the effects of radiation, convection, and turbulent mixing driven by the Balbus-Hawley instability, in astronomical systems ranging from dwarf novae (DNe), and soft X-ray transients (SXTs), to active galactic nuclei (AGN). In order to account for the interplay between convective and turbulent energy transport in a shear...

Data from the near-wall region of an attached and a separated turbulent boundary layer are used for the development of near-wall damping functions utilized in turbulence modelling. The model considered is an explicit algebraic Rey-nolds stress model. The data are taken from two direct numerical simulations. The turbulent boundary layer equation is analyzed in order to extend the validity of exi...