Track velocity control of crawler type underwater mining robot through shallow-water test

2012 ◽  
Vol 26 (10) ◽  
pp. 3291-3298 ◽  
Author(s):  
Suk-Min Yoon ◽  
Sup Hong ◽  
Sung-Jea Park ◽  
Jong-Su Choi ◽  
Hyung-Woo Kim ◽  
...  
Keyword(s):  
Shallow Water ◽  
Velocity Control ◽  
Water Test ◽  
Underwater Mining

scholarly journals Controlling the Computational Modes of the Arbitrarily Structured C Grid

2012 ◽  
Vol 140 (10) ◽  
pp. 3220-3234 ◽  
Author(s):  
Hilary Weller
Keyword(s):  
Shallow Water ◽  
Flow Direction ◽  
Water Model ◽  
Test Cases ◽  
Continuous Linear ◽  
Shallow Water Model ◽  
Advection Schemes ◽  
Water Test ◽  
Better Than ◽  
Potential Enstrophy

Abstract The arbitrarily structured C grid, Thuburn–Ringler–Skamarock–Klemp (TRiSK), is being used in the Model for Prediction Across Scales (MPAS) and is being considered by the Met Office for their next dynamical core. However, the hexagonal C grid supports a branch of spurious Rossby modes, which lead to erroneous grid-scale oscillations of potential vorticity (PV). It is shown how these modes can be harmlessly controlled by using upwind-biased interpolation schemes for PV. A number of existing advection schemes for PV are tested, including that used in MPAS, and none are found to give adequate results for all grids and all cases. Therefore a new scheme is proposed; continuous, linear-upwind stabilized transport (CLUST), a blend between centered and linear-upwind with the blend dependent on the flow direction with respect to the cell edge. A diagnostic of grid-scale oscillations is proposed that gives further discrimination between schemes than using potential enstrophy alone. Indeed, some schemes are found to destroy potential enstrophy while grid-scale oscillations grow. CLUST performs well on hexagonal-icosahedral grids and unrotated skipped latitude–longitude grids of the sphere for various shallow-water test cases. Despite the computational modes, the hexagonal icosahedral grid performs well since these modes are easy and harmless to filter. As a result, TRiSK appears to perform better than a spectral shallow-water model.

Spectral Transform Solutions to the Shallow Water Test Set

1995 ◽  
Vol 119 (1) ◽  
pp. 164-187 ◽  
Author(s):  
Ruediger Jakob-Chien ◽  
James J. Hack ◽  
David L. Williamson
Keyword(s):  
Shallow Water ◽  
Test Set ◽  
Spectral Transform ◽  
Water Test

Paper 10: Radial Forces in Centrifugal Pumps with Guide Vanes

1969 ◽  
Vol 184 (14) ◽  
pp. 101-107 ◽  
Author(s):  
P. Hergt ◽  
P. Krieger
Keyword(s):  
Pressure Distribution ◽  
Shallow Water ◽  
Experimental Test ◽  
Centrifugal Pumps ◽  
Test Rig ◽  
Guide Vanes ◽  
Water Test ◽  
Small Flow ◽  
Radial Forces ◽  
Load Conditions

At partial and overload conditions, radial decentralizing forces act upon the rotor of a centrifugal pump with guide vanes if the impeller is out of centre. The magnitude of these forces depends on load conditions, and the forces increase with growing eccentricity. At very small flow, these forces become non-stationary. They rotate at a considerably lower frequency than the velocity frequency and may lead to rotor vibrations. The paper discusses the effects of stationary and non-stationary radial forces, and resulting shaft deflections and vibrations, from measurements on two experimental test rigs. The paper also presents the results of research on the pressure distribution of guide vanes, carried out in air, and gives observations of flow patterns in a shallow water test rig.

An Incremental Remapping Transport Scheme on a Spherical Geodesic Grid

2005 ◽  
Vol 133 (8) ◽  
pp. 2335-2350 ◽  
Author(s):  
William H. Lipscomb ◽  
Todd D. Ringler
Keyword(s):  
Shallow Water ◽  
Climate Models ◽  
Water Model ◽  
Test Cases ◽  
Tracer Transport ◽  
Water Ice ◽  
Flux Corrected Transport ◽  
Weather And Climate ◽  
Water Test ◽  
Monotonicity Preserving

Abstract Weather and climate models contain equations for transporting conserved quantities such as the mass of air, water, ice, and associated tracers. Ideally, the numerical schemes used to solve these equations should be conservative, spatially accurate, and monotonicity-preserving. One such scheme is incremental remapping, previously developed for transport on quadrilateral grids. Here the incremental remapping scheme is reformulated for a spherical geodesic grid whose cells are hexagons and pentagons. The scheme is tested in a shallow-water model with both uniform and varying velocity fields. Solutions for standard shallow-water test cases 1, 2, and 5 are obtained with a centered scheme, a flux-corrected transport (FCT) scheme, and the remapping scheme. The three schemes are about equally accurate for transport of the height field. For tracer transport, remapping is far superior to the centered scheme, which produces large overshoots, and is generally smoother and more accurate than FCT. Remapping has a high startup cost associated with geometry calculations but is nearly twice as fast as FCT for each added tracer. As a result, remapping is cheaper than FCT for transport of more than about seven tracers.

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