Browsing by Author "Young, Alwin"

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    Hydraulic Transient Analysis for the Culver-Goodman Tunnel Rochester, New York
    (St. Anthony Falls Hydraulic Laboratory, 1975-12) Song, Charles; Ring, Timothy; Young, Alwin; Leung, Kim
    This report describes a mixed-flow hydraulic transient model for the Culver-Goodman Tunnel of Rochester, New York. The model is based on the one-dimensional unsteady partial differential equations for open channels and closed conduits. These differential equations are solved numerically using the method of characteristics. Thus, the model is capable of dealing with the rapidly changing water hammer pressures and surges in a complex system. Hydrographs at 18 dropshafts due to a 5 year storm are used as the inputs. Outflow hydrographs, storage, depth or piezometric head, and velocity at 104 stations at small time intervals are obtained as output.
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    A Study of Flow over Ventilated Discontinuities in a Boundary Layer
    (St. Anthony Falls Hydraulic Laboratory, 1969-06) Ward, Bruce; Young, Alwin; Anderson, Alvin G.
    At present hydrodynamicists are critically interested in ventilation as a means of vessel guidance and control. The injection of air into the boundary layer can also produce significant drag reduction benefits and cushion an abruptly changing flow boundary against the severity of cavitation damage in high velocity flows. This report describes an experimental investigation of the characteristics of ventilated cavities situated in a boundary layer and their effects, including drag reduction. Study cases include free surface flows over ventilated boundary discontinuities in the form of a step, a slot, and a break-in-grade. The observed cavities are generally similar to those found in the wake of supercavitating hydrofoils. The quantitative results refer to cavity length, air supply coefficient, and ventilation parameter, The maximum drag reduction obtained with a ventilated slot in a boundary layer over the smooth surface in the fully wetted case was on the order of fifteen per cent. The average flow velocity for the drag reduction experiment was from ten to nineteen feet per second. Empirical cavity results are also compared with irrotational linearized potential flow theory in the appendix. Only the step experiment showed good agreement with theory.