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This paper gives, in the limit of infinite Froude number, a closed-form, analytical solution for steady, two-dimensional, irrotational, infinite-depth, free-surface, attached flow over a submerged tandem cascade of hydrofoils for arbitrary angle of attack, depth of submergence and interfoil separation. The multiply connected flow domain is conformally mapped to a concentric annulus in an auxiliary plane. The complex flow potential and its derivative, the complex velocity, are obtained in the auxiliary plane by considering their form at known special points in the flow and the required conformal mapping is determined by explicit integration, allowing accurate evaluation of various flow quantities including the lift on each foil. The circulation around the foils causes the foil array to act as a row of point vortices, or a shear layer, and so, for positive angles of attack, the flow speed at the free surface can substantially exceed the speed at depth, with the speeds simply related through the lift coefficient. Decreasing the interfoil separation decreases the disturbance to the free surface and greatly increases the lift per hydrofoil, thus allowing for the shallower operation of a hydrofoil array than of an isolated foil for a given lift requirement. Further, the flow over a hydrofoil array approaches its infinite depth form significantly more rapidly than that over an isolated foil. In contrast to the infinite-submergence case where a through-array flow can be imposed, in the finite submergence case, periodicity and the presence of the free surface mean that there is no net flow between the foils. [ABSTRACT FROM AUTHOR]

Since early manned space flight orographically forced cloud patterns have been described in terms of the single isolated shock structure of shallow-water flow or, equivalently, compressible fluid flow. Some of these observations show, behind an initial 'bow wave,' a series of almost parallel wave crests. This paper considers the simplest extension of shallow-water theory that retains not only nonlinear steepening of waves but includes departures from hydrostatic balance, and thus wave dispersion, showing that the single shocks of shallow-water theory are transformed into multiple parallel finite-amplitude wave crests. The context of the discussion is the forced Kadomtsev--Petviashvili equation from classical ship wave dynamics, which plays the same role in two-dimensional near-critical fluid flow as the more familiar Korteweg-de Vries equation in one-dimensional flow. The drag and flow regimes in near-critical flow over isolated orography are described in terms of the three governing parameters of the flow: the deviation of the flow speed from critical, the strength of nonhydrostatic effects, and the strength of orographic forcing.

A complete theory of free torsion and bending of anisotropic thin-walled beams with closed cross-sectional contours is developed using the stress formulation. In contrast to a displacement formulation that is traditionally used for this purpose, the stress formulation does not require the introduction of assumptions concerning the form of the warping function. The advantage of the stress formulation is the exact satisfaction of the equilibrium equations, which provides more accurate results for beams whose stiffness coefficients depend on the contour coordinate, for example, beams stiffened with stringers. Approximate compatibility conditions obtained with the aid of Castigliano's theorem describe all possible types of coupling effects and give explicit expressions for displacements of a beam with an arbitrary cross-sectional contour and material anisotropy. Theoretical results are compared to experimental data, and fair agreement is found.

A new study evaluates the thermal inactivation of Listeria innocua and Salmonella spp. in chicken patties processed in air convection ovens.

a new study compares the thermal inactivation of Listeria and Salmonella in ground chicken breast meat with that in a peptone-agar solution.

The stability of horizontal shear flow over an infinite ridge was examined in two distinct limits. Equations for barotropic flow with rigid lids over top-hat and multistep ridge profiles and longwaves in continuously stratified flow over a top-hat profile were formulated and solved. Results showed that the instability in all cases occur when equivalent waves are brought relatively to rest with an opposing wave on the opposite side of the ridge. An application to the mid-ocean ridge in the South Pacific is also described.

The effect of different cooking methods on thermal deactivation of foodborne pathogens like Salmonella Senftenberg and Listeria innocua, which are present in meat and poultry products, is examined. The relationship between cooking time and survival rate of pathogens is analyzed using mathematical models.