The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform
F Mohammed - One of the best experts on this subject based on the ideXlab platform.
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physical modeling of tsunamis generated by three dimensional deformable granular landslides
Journal of Geophysical Research, 2012Co-Authors: F Mohammed, Hermann M FritzAbstract:[1] Tsunamis generated by deformable granular landslides are physically modeled in a three-dimensional tsunami wave basin based on the generalized Froude Similarity. The dynamic landslide impact characteristics were controlled by means of a novel pneumatic landslide generator. The wave amplitudes, periods, and wavelengths are related to the landslide parameters at impact with the landslide Froude number being a dominant parameter. Between 1 and 15% of the landslide kinetic energy at impact is converted into the wave train energy. The wave amplitudes decay in radial and angular directions from the landslide axis. The first wave crest mostly travels with speeds close to the theoretical approximation of the solitary wave speed. The measured tsunami wave profiles were either of the nonlinear oscillatory or nonlinear transition type depending primarily on the landslide Froude number and relative slide thickness at impact. The generated waves range from shallow to deep water depth regimes, with the majority being in the intermediate water depth regime. Wave characteristics are compared with other two- and three-dimensional landslide tsunami studies and the results are discussed.
Elisha Moses - One of the best experts on this subject based on the ideXlab platform.
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from flutter to tumble inertial drag and Froude Similarity in falling paper
Physical Review Letters, 1998Co-Authors: Andrew Belmonte, H S Eisenberg, Elisha MosesAbstract:In an experiment on thin flat strips falling through a fluid in a vertical cell, two fundamental motions are observed: side-to-side oscillation (flutter) and end-over-end rotation (tumble). At high Reynolds number, the dimensionless Similarity variable describing the dynamics is the Froude number $\mathrm{Fr}$, being the ratio of characteristic times for downward motion and pendular oscillations. The transition from flutter to tumble occurs at ${\mathrm{Fr}}_{c}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.67\ifmmode\pm\else\textpm\fi{}0.05$. We propose a phenomenological model including inertial drag and lift which reproduces this motion, and directly yields the Froude Similarity.
Wei Bing-qian - One of the best experts on this subject based on the ideXlab platform.
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Estimation of bed load transport rate based on grain Froude Similarity
Journal of Heilongjiang Hydraulic Engineering College, 2000Co-Authors: Wei Bing-qianAbstract:An estimation method of bed load transport rate based on the grain Froude Similarity is proposed.The usefulness of this estimation method is verified by using the bed load transport rates obtained from the large scale experimental flume and transported from the inflow rivers into the Taisetsu dam reservoir.
Hermann M Fritz - One of the best experts on this subject based on the ideXlab platform.
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physical modeling of tsunamis generated by three dimensional deformable granular landslides
Journal of Geophysical Research, 2012Co-Authors: F Mohammed, Hermann M FritzAbstract:[1] Tsunamis generated by deformable granular landslides are physically modeled in a three-dimensional tsunami wave basin based on the generalized Froude Similarity. The dynamic landslide impact characteristics were controlled by means of a novel pneumatic landslide generator. The wave amplitudes, periods, and wavelengths are related to the landslide parameters at impact with the landslide Froude number being a dominant parameter. Between 1 and 15% of the landslide kinetic energy at impact is converted into the wave train energy. The wave amplitudes decay in radial and angular directions from the landslide axis. The first wave crest mostly travels with speeds close to the theoretical approximation of the solitary wave speed. The measured tsunami wave profiles were either of the nonlinear oscillatory or nonlinear transition type depending primarily on the landslide Froude number and relative slide thickness at impact. The generated waves range from shallow to deep water depth regimes, with the majority being in the intermediate water depth regime. Wave characteristics are compared with other two- and three-dimensional landslide tsunami studies and the results are discussed.
K E Hansen - One of the best experts on this subject based on the ideXlab platform.
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an empirical velocity scale relation for modelling a design of large mesh pelagic trawl
Fisheries Research, 1996Co-Authors: R S T Ferro, B Van Marlen, K E HansenAbstract:Abstract Physical models of fishing nets are used in fishing technology research at scales of 1:40 or smaller. As with all modelling involving fluid flow, a set of rules is required to determine the geometry of the model and its velocity relative to the water. Appropriate rules ensure that the model is subject to similar forces and behaves in a similar way to the full-scale net. It is not possible however, to choose a completely compatible set of modelling rules and a compromise is necessary. The common practice is to assume that Similarity is achieved when a constant Froude Number is maintained. This is often found to be inadequate in that drag is increasingly overestimated as the scale is reduced. A new empirical relation between net drag coefficient and Reynolds Number at constant net geometry for one design of large mesh pelagic trawl is derived which applies over a wide range of Reynolds Numbers (based on mean twine thickness) from 63 to 1.67 × 104. Six sizes of the same net design from full-scale to 1:40 were investigated. From this relation a new velocity scale relation has been proposed which relates velocity scale to linear scale for this particular trawl design. It is argued that not only the net mouth but also all the individual netting panels will maintain the correct geometry over this range of model sizes. The traditional Froude Similarity law states that the velocity scale is equal to the linear scale to the power of 0.5. The new relation suggests a power of approximately 0.6. Lower velocities may be necessary to compensate for the increase in drag coefficient as Reynolds Number decreases at constant Froude Number. Until more experiments are done on radically different net designs it will not be possible to assess how widely this new relation may apply.
