scholarly journals RECREATIONAL SURFING ON HAWAIIAN REEFS

1972 ◽  
Vol 1 (13) ◽  
pp. 147 ◽  
Author(s):  
James R. Walker ◽  
Robert Q. Palmer ◽  
Joseph K. Kukea
Keyword(s):  
Coastal Zone ◽  
Three Dimensional ◽  
Hydraulic Model ◽  
Small Scale ◽  
Ocean Bottom ◽  
Model Studies ◽  
Model Study

Recreational surfing has been studied in Hawaii to develop criteria for the preservation, enhancement and design of surf sites. The criteria will aid in planning compatible uses of the coastal zone. Surfing characteristics and wave transformations were studied in the field and related to ocean bottom features at prime surf sites. A small scale, three dimensional, hydraulic model study was conducted to determine the effect that a given bottom feature had upon the surfing wave. A concept of a multiple-purpose surfing shoal to be compatible with several varied interests in the coastal zone was hypothesized from field, analytic, and model studies.

Model Study of Waves Generated by Convection with Direct Validation via Satellite

2010 ◽  
Vol 67 (5) ◽  
pp. 1617-1631 ◽  
Author(s):  
Alison W. Grimsdell ◽  
M. Joan Alexander ◽  
Peter T. May ◽  
Lars Hoffmann
Keyword(s):  
Gravity Waves ◽  
Three Dimensional ◽  
Early Morning ◽  
Wave Pattern ◽  
Global Scale ◽  
Major Effect ◽  
Small Scale ◽  
Model Studies ◽  
Model Study ◽  
Cloud Resolving Model

Abstract Atmospheric gravity waves have a major effect on atmospheric circulation, structure, and stability on a global scale. Gravity waves can be generated by convection, but in many cases it is difficult to link convection directly to a specific wave event. In this research, the authors examine an event on 12 January 2003 when convective waves were clearly generated by a period of extremely intense rainfall in the region of Darwin, Australia, during the early morning. The waves were observed by the Atmospheric Infrared Sounder (AIRS) instrument on board the Aqua satellite, and a dry version of a nonlinear, three-dimensional mesoscale cloud-resolving model is used to generate a comparable wave field. The model is forced by a spatially and temporally varying heating field obtained from a scanning radar located north of Darwin at Gunn Point. With typical cloud-resolving model studies it is generally not possible to compare the model results feature-for-feature with observations since although the model precipitation and small-scale heating may be similar to observations, they will occur at different locations and times. In this case the comparison is possible since the model is forced by the observed heating pattern. It is shown that the model output wave pattern corresponds well to the wave pattern observed by the AIRS instrument at the time of the AIRS overpass.

scholarly journals MOVABLE-BED MODEL STUDIES OF PERCHED BEACH CONCEPT

1972 ◽  
Vol 1 (13) ◽  
pp. 60
Author(s):  
C.B. Chatham
Keyword(s):  
Three Dimensional ◽  
Normal Wave ◽  
Beach Erosion ◽  
Model Studies ◽  
Model Study ◽  
Wide Range ◽  
Final Design ◽  
Storm Wave ◽  
Wave Conditions ◽  
Movable Bed

Hydraulic model studies were conducted to aid in ascertaining the technical feasibility and optimum design factors of the perched beach concept. Among these were two-dimensional, movable-bed studies to determine an estimate of the amount of sand which would be lost seaward over the submerged toe structure by normal and storm wave action, the optimum elevation of the submerged toe structure, and the length of a stone blanket required to reduce seaward migration of sand to a minimum. The model beach was subjected to test waves until equilibrium was reached for a wide range of wave conditions for both the existing beach and the perched beach. Test results indicate that (a) little or no beachfill material will be lost seaward of the toe structure for normal wave conditions but the larger storm waves may cause erosion of the perched beach, (b) the installation of a stone blanket shoreward of the toe structure will reduce the amount of beach erosion, (c) if the beach fill is extended a sufficient distance seaward, the toe structure serves no useful purpose, and (d) a three-dimensional movable-bed model study is feasible and is necessary to determine the final design features of a perched beach.

scholarly journals HYDRAULIC MODEL TESTS FOR INDIANA HARBOR DEVELOPMENT

2000 ◽  
Vol 1 (4) ◽  
pp. 26
Author(s):  
Lorenz G. Straub ◽  
Robert Y. Hudson
Keyword(s):  
Construction Projects ◽  
Lake Michigan ◽  
Hydraulic Model ◽  
Model Tests ◽  
Small Scale ◽  
Steel Company ◽  
Model Studies ◽  
Plant Expansion ◽  
Under Construction ◽  
Future Plans

Plant facilities of the Inland Steel Company, East Chicago, Indiana, and the East Chicago plant of the Youngstown Sheet and Tube Company, occupy the entire perimeter and adjacent shoreline of Indiana Harbor (Figs. 1, 2, and 3) Major changes in the plants of these companies required revisions in the shoreline and the building of various bulkheads within the harbor and in Lake Michigan outside the harbor breakwater. Small scale hydraulic model studies of the harbor and portions of certain harbor structures were conducted to aid in the solution in the wave action problems arising from the construction programs of the two steel companies. Investigations concerned construction projects recently completed, projects under construction during the course of the model studies, and proposed future plans for plant expansion and harbor development.

scholarly journals TURBULENT OSCILLATORY FLOW OVER RIPPLES AT HIGH REYNOLDS NUMBERS FOR PETA-SCALE SIMULATIONS

2018 ◽  
pp. 95
Author(s):  
Guillermo Oyarzun ◽  
Athanassios Dimas
Keyword(s):  
Coastal Zone ◽  
High Performance ◽  
Oscillatory Flow ◽  
Three Dimensional ◽  
Small Scale ◽  
Poisson Solver ◽  
Execution Model ◽  
High Reynolds ◽  
Wave Induced ◽  
The Impact

Surface waves in the coastal zone induce oscillatory flow motions in the vicinity of the seabed. These wave-induced coastal flows interact with the sandy seabed and modify the bed shape by generating coherent small-scale bed structures, which are generally known as ripples. The presence of ripples in oscillatory flows is important due to the impact they have on the seabed roughness and how they affect the near-bed boundary layer hydrodynamics. Simulations of higher and more real-scale Reynolds number (Re) require the use of supercomputers in order to obtain results in a reasonable amount of time. However, the constant evolution of the computing facilities makes the development of parallel algorithms a rather difficult task. The objective of the proposed research is to advance in the comprehension of coastal processes utilizing high performance computing (HPC) for the numerical simulation of the three-dimensional, turbulent flow, which is induced in the coastal zone by wave propagation. In particular, our CFD code (SimuCoast) has been developed using a hybrid MPI+OpenACC execution model that increases its scalability and allows it to engage the vast majority of high-end supercomputers. Special attention has been paid in the parallelization strategy of the Poisson solver that is the most computational demanding operation.

A Synopsis of Cooling Tower Pump Sump Modeling Experience

2003 ◽  
Author(s):  
David E. Werth
Keyword(s):  
Physical Model ◽  
Cooling Tower ◽  
Hydraulic Model ◽  
Design Standards ◽  
Model Studies ◽  
Model Study ◽  
Pump Sump ◽  
Performance Comparisons

Cooling tower pump sumps are often designed according to the Hydraulic Institute (HI) Standards [1]. However, when geometric or economic limitations lead to deviations from these standards, a physical hydraulic model study is often conducted. This paper summarizes a number of recent physical model studies and brings to attention some of the recurring problems observed during the physical model studies. Performance comparisons are made between stations strictly adhering to the established design standards and those with minor or significant variations.

scholarly journals Evaluating the Structure from Motion Technique for Measurement of Bed Morphology in Physical Model Studies

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 998
Author(s):  
Sanat Kumar Karmacharya ◽  
Nils Ruther ◽  
Ujjwal Shrestha ◽  
Meg Bahadur Bishwakarma
Keyword(s):  
Physical Model ◽  
Structure From Motion ◽  
Point Cloud ◽  
Three Dimensional ◽  
Time Frame ◽  
Model Studies ◽  
Model Study ◽  
Skilled Personnel ◽  
Dense Point ◽  
Point Data

The selection of instrumentation for data acquisition in physical model studies depends on type and resolution of data to be recorded, time frame of the model study, available instrumentation alternatives, availability of skilled personnel and overall budget of the model study. The available instrumentation for recording bed levels or three-dimensional information on geometry of a physical model range from simple manual gauges to sophisticated laser or acoustic sensors. In this study, Structure from Motion (SfM) technique was applied, on three physical model studies of different scales and study objectives, as a cheap, quicker, easy to use and satisfactorily precise alternative for recording 3D point data in form of colour coded dense point cloud representing the model geometry especially the river bed levels in the model. The accuracy of 3D point cloud generated with SfM technique were also assessed by comparing with data obtained from manual measurement using conventional surveying technique in the models and the results were found to be very promising.

Hydraulic model study for the design of the Wreck Cove control gates

1980 ◽  
Vol 7 (2) ◽  
pp. 304-314 ◽  
Author(s):  
D. S. Weaver ◽  
W. W. Martin
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Hydraulic Model ◽  
Two Dimensional ◽  
Cape Breton ◽  
Model Study ◽  
Vertical Lift ◽  
Lift Control ◽  
Closed Conduit ◽  
Power Project

An hydraulic model study was carried out to estimate the discharge and downpull characteristics of the vertical lift control gates proposed for the Wreck Cove power project in the Cape Breton Highlands. The same gate geometry was selected with the two different upstream tunnel configurations of the Gisborne and McMillan reservoir–outlet structures. In the former, both free-surface and closed-conduit downstream conditions could occur in the prototype, whereas only closed-conduit flow would exist in the latter. In addition, the gate model was elastically suspended so that its susceptibility to flow-induced oscillations could be assessed. The entire test section was installed in a high-speed water tunnel for testing.The gate-bottom geometry was chosen on the basis of previously reported results with two-dimensional models. The three-dimensional features included in the present model (e.g., gate slots) did not yield downpull or vibration characteristics significantly different from the two-dimensional results. The advantages of the present gate configuration are discussed with respect to simpler but unsatisfactory systems.

Extrusion-Based 3D Printing for Pharmaceuticals: Contemporary Research and Applications

2019 ◽  
Vol 24 (42) ◽  
pp. 4991-5008 ◽  
Author(s):  
Mohammed S. Algahtani ◽  
Abdul Aleem Mohammed ◽  
Javed Ahmad
Keyword(s):  
Cosmetic Surgery ◽  
Fused Deposition Modeling ◽  
Personalised Medicine ◽  
Organ Transplant ◽  
Three Dimensional ◽  
Dosage Forms ◽  
Release Profile ◽  
Small Scale ◽  
Drug Release Profile ◽  
Fused Deposition

Three-dimensional printing (3DP) has a significant impact on organ transplant, cosmetic surgery, surgical planning, prosthetics and other medical fields. Recently, 3 DP attracted the attention as a promising method for the production of small-scale drug production. The knowledge expansion about the population differences in metabolism and genetics grows the need for personalised medicine substantially. In personalised medicine, the patient receives a tailored dose and the release profile is based on his pharmacokinetics data. 3 DP is expected to be one of the leading solutions for the personalisation of the drug dispensing. This technology can fabricate a drug-device with complicated geometries and fillings to obtain the needed drug release profile. The extrusionbased 3 DP is the most explored method for investigating the feasibility of the technology to produce a novel dosage form with properties that are difficult to achieve using the conventional industrial methods. Extrusionbased 3 DP is divided into two techniques, the semi-solid extrusion (SSE) and the fused deposition modeling (FDM). This review aims to explain the extrusion principles behind the two techniques and discuss their capabilities to fabricate novel dosage forms. The advantages and limitations observed through the application of SSE and FDM for fabrication of drug dosage forms were discussed in this review. Further exploration and development are required to implement this technology in the healthcare frontline for more effective and personalised treatment.

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