A standard Instron testing machine, in which crosshead displacement varies linearly with time was modified so that crosshead displacement varies exponentially with time. This change permits testing at constant Hencky strain rate (c = fi/8), which provides a constant stretch history for both simple extensional flow and strip biaxial extensional flow. This results in a visualization of the steady...

We present a new algorithm for combining a fully anisotropic goal-oriented mesh adaptation with the transient fixed point method for unsteady problems. The minimization of the error on a functional provides both the density and the anisotropy (stretching) of the optimal mesh. This method is used for specifying the mesh for a time subinterval from the state and the adjoint. The global transient ...

The influence of enforced periodic concentration variations on a continuous stirred tank reactor was studied theoretically. The unsteady-state-processing becomes advantageous under certain conditions. This can be shown for an irreversible consecutive-competing reaction. The yield and selectivitv of the intermediate oroduct can exceed the values obtainable at steady-state-processing in the menti...

AD-P004 168 AD-P004 169 TITLE: Superroaneuverability. Wing Rock Flov Phenomena. Potential Applications of Forced Unsteady Flows. Unsteady Stall Penetration of an Oscillating Swept Wing. Simultaneous Flow Visualization and Unsteady Lift Measurement on an Oscillating Lifting Surface. A Visual Study of a Delta Wing in Steady and Unsteady Motion. Comparative Visualization of Accelerating Flow aroun...

The goal of this paper is to investigate jump conditions for unsteady small perturbations at impermeable interfaces, slip or bonded, plane or not, between fluids and structures in the presence of initial flow and prestress. Based on conservative equations obtained from a mixed Eulerian-Lagrangian description, interface conditions are first derived in an elegant and straightforward manner thanks...

Initial results of an ongoing Navier-Stokes Computational Fluid Dynamics study of horizontal axis tidal current turbine hydrodynamics are presented. Part of the underlying motivation is assessing the effects of the Reynolds number on turbine performance and loads in steady and unsteady flow regimes. The study aims at a) providing initial verification and validation of Navier-Stokes CFD for stea...

New analytic solutions for unsteady magnetohydrodynamic (MHD) flows of a generalized second-grade fluid have been derived. The generalized second-grade fluid saturates the porous space. Fractional derivative is used in the governing equation. The analytical expressions for velocity and shear stress fields have been obtained by using Laplace transform technique for the fractional calculus. The o...

The determination of the optimal distribution of the catalytic activity profile, whichmaximizes the catalytic effectiveness, in created unsteady state conditions, is analyzed andtreated numerically for the case of a simple reaction. It was proven that the modulation, of thetemperature and the reactant concentration of the external bulk fluid, leads to a considerableincrease of the catalytic eff...