The Design Limitations of a Circular Wave Pool

2014 ◽  
Author(s):  
Steven A. Schmied ◽  
Jonathan R. Binns ◽  
Martin R. Renilson ◽  
Giles A. Thomas ◽  
Gregor J. Macfarlane ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Wave Structure ◽  
Breaking Waves ◽  
Experimental Results ◽  
Scale Model ◽  
Pressure Source ◽  
Signal Tracking ◽  
Wave Disturbances ◽  
Sloping Beach ◽  
Parameter Values

In this paper, the design of a circular wave pool that produces continuously breaking waves is discussed, whereby a pressure source is rotated within an annular wave pool. The concept was that the pressure source generates non-breaking waves that propagate inward to the inner ring of the annulus, where a sloping bathymetry (beach) triggers wave breaking. In order to refine the technique, research was conducted to better understand the mechanics of waves generated by moving pressure sources in a constrained waterway, the transformation of these waves as they travel across the channel and the effect of the sloping beach on the wave quality for surfing. The quality of the waves was defined in terms of wave height, speed and shape, with the aim to create plunging waves, known as “barrels”, that are highly desired by surfers. A predominantly experimental approach was undertaken to determine the required design parameter values and their limitations. Scale model experimental results were previously presented at OMAE 2011 and OMAE2013. This paper presents the steps to design the pool using the empirical analysis and experimental results are presented. The effect of the pressure source and pool bathymetry on the currents formed in the pool, are also presented. Through this design process, high quality continuous breaking waves with the desired plunging shape were able to be generated. Finally, the authors are planning to use the facilities and techniques developed to investigate the complexities of predefined wave fields, including the three dimensional (3D) details of the velocity, pressure and turbulence fields beneath. Understanding these complexities within multidimensional wave patterns is the key to analysing a number of different fields, including wave resistance of ships; wave disturbances to other maritime users; bank erosion; wave signal tracking; and wave structure interaction.

scholarly journals An Experimental and Computational Investigation of Flow in a Radial Inlet of an Industrial Pipeline Centrifugal Compressor

1994 ◽  
Author(s):  
M. B. Flathers ◽  
G. E. Bache ◽  
R. Rainsberger
Keyword(s):  
Centrifugal Compressor ◽  
Numerical Study ◽  
Three Dimensional ◽  
Experimental Results ◽  
Scale Model ◽  
Navier Stokes ◽  
Angle Distribution ◽  
Computational Results ◽  
Industrial Pipeline ◽  
Design Schedule

The flowfield of a complex three dimensional radial inlet for an industrial pipeline centrifugal compressor has been experimentally determined on a half scale model. Based on the experimental results, inlet guide vanes have been designed to correct pressure and swirl angle distribution deficiencies. The unvaned and vaned inlets are analyzed with a commercially available fully 3D viscous Navier-Stokes code. Since experimental results were available prior to the numerical study, the unvaned analysis is considered a postdiction while the vaned analysis is considered a prediction. The computational results of the unvaned inlet have been compared to the previously obtained experimental results. The experimental method utilized for the unvaned inlet is repeated for the vaned inlet and the data has been used to verify the computational results. The paper will discuss experimental, design and computational procedures, grid generation, boundary conditions, and experimental versus computational methods. Agreement between experimental and computational results is very good, both in prediction and postdiction modes. The results of this investigation indicate that CFD offers a measurable advantage in design, schedule and cost and can be applied to complex, three dimensional radial inlets.

Wave-in-Deck Loads for an Intricate Pile-Supported Pier and Variation With Deck Clearance

2013 ◽  
Author(s):  
Andrew Cornett ◽  
David Anglin ◽  
Trevor Elliott
Keyword(s):  
Water Waves ◽  
Three Dimensional ◽  
Wave Structure ◽  
Physical Modelling ◽  
Interaction Process ◽  
Air Gap ◽  
Scale Model ◽  
Shallow Water Waves ◽  
Structure Interaction ◽  
Wave Structure Interaction

Many deck structures are located at elevations low enough to be impacted by large waves. However, due to the highly complex and impulsive nature of the interactions between wave crests and intricate deck structures, establishing reliable estimates of extreme pressures and forces for use in design remains challenging. In this paper, results from an extensive set of three-dimensional scale model tests conducted to support the design of a large pile-supported pier (or jetty) are presented and discussed. Relationships between maximum wave-in-deck loads and the deck clearance (air gap) are presented and discussed. Results from numerical simulations of the wave-structure interaction process obtained using the three-dimensional CFD software FLOW-3D® are also presented and discussed. Finally, some initial comparisons between the numerical and physical modelling are also included. This paper provides new insights concerning the character and magnitude of the hydrodynamic pressures and loads exerted on intricate pile-supported deck structures due to impact by non-linear shallow-water waves, and the relationships between the hydrodynamic forcing and the deck clearance or air gap.

An Experimental and Computational Investigation of Flow in a Radial Inlet of an Industrial Pipeline Centrifugal Compressor

1996 ◽  
Vol 118 (2) ◽  
pp. 371-384 ◽  
Author(s):  
M. B. Flathers ◽  
G. E. Bache ◽  
R. Rainsberger
Keyword(s):  
Centrifugal Compressor ◽  
Numerical Study ◽  
Three Dimensional ◽  
Experimental Results ◽  
Scale Model ◽  
Navier Stokes ◽  
Angle Distribution ◽  
Computational Results ◽  
Industrial Pipeline ◽  
Design Schedule

The flow field of a complex three-dimensional radial inlet for an industrial pipeline centrifugal compressor has been experimentally determined on a half-scale model. Based on the experimental results, inlet guide vanes have been designed to correct pressure and swirl angle distribution deficiencies. The unvaned and vaned inlets are analyzed with a commercially available fully three-dimensional viscous Navier–Stokes code. Since experimental results were available prior to the numerical study, the unvaned analysis is considered a postdiction while the vaned analysis is considered a prediction. The computational results of the unvaned inlet have been compared to the previously obtained experimental results. The experimental method utilized for the unvaned inlet is repeated for the vaned inlet and the data have been used to verify the computational results. The paper will discuss experimental, design, and computational procedures, grid generation, boundary conditions, and experimental versus computational methods. Agreement between experimental and computational results is very good, both in prediction and postdiction modes. The results of this investigation indicate that CFD offers a measurable advantage in design, schedule, and cost and can be applied to complex, three-dimensional radial inlets.

A Novel Method for Generating Continuously Surfable Waves

2010 ◽  
Vol 44 (2) ◽  
pp. 7-12 ◽  
Author(s):  
Steven Schmied ◽  
Jonathan Binns ◽  
Martin Renilson ◽  
Giles Thomas ◽  
Gregor Macfarlane ◽  
...  
Keyword(s):  
Steady State ◽  
Wave Breaking ◽  
Numerical Study ◽  
River Estuary ◽  
Breaking Waves ◽  
Scale Model ◽  
Wave Mechanics ◽  
Pressure Source ◽  
Novel Method ◽  
Future Work

AbstractThis paper presents the background and initial investigation of a novel method for generating continuously surfable waves utilizing a moving pressure source. The idea is to produce continuous breaking waves using a pressure source that is rotated within an annular wave pool. The inner ring of the annulus has a sloping bathymetry to induce wave breaking. The underlying aim of the project is to understand the wave mechanics, to allow the creation of repeatable continuous “steady-state” waves.The immediate benefits of this scientific investigation will be realized by engineering the results into a surfing wave pool for recreational health use. The longer-term benefits will be developed through fundamental investigations of breaking waves.Preliminary experiments into creating a continuous steady-state wave were conducted in a towing tank using a series of pressure sources. The results have then been used to validate an initial numerical study. In addition, qualitative, full-scale experiments were carried out using a fishing vessel in a river estuary. This paper reports on the research conducted to date and plans for future work, including conducting experiments utilizing a 10-metre-diameter scale model.

A Novel Method for Generating Continuously Surfable Waves: Comparison of Predictions With Experimental Results

2011 ◽  
Author(s):  
Steven A. Schmied ◽  
Jonathan R. Binns ◽  
Martin R. Renilson ◽  
Giles A. Thomas ◽  
Gregor J. Macfarlane ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Experimental Investigation ◽  
Wave Breaking ◽  
Breaking Waves ◽  
Experimental Results ◽  
Pressure Source ◽  
Towing Tank ◽  
Novel Method ◽  
The Waves

In this paper, a novel idea to produce continuous breaking waves is discussed, whereby a pressure source is rotated within an annular wave pool. The concept is that the inner ring of the annulus has a sloping bathymetry to induce wave breaking from the wake of the pressure source. In order to refine the technique, work is being conducted to better understand the mechanics of surfable waves generated by moving pressure sources in restricted water. This paper reports on the first stage of an experimental investigation of a novel method for generating continuously surfable waves utilising a moving pressure source. The aim was to measure and assess the waves generated by two parabolic pressure sources and a wavedozer [1] for their suitability for future development of continuous breaking surfable waves. The tests were conducted at the Australian Maritime College (AMC), University of Tasmania (UTas) 100 metre long towing tank. The experimental results as variations in wave height (H) divided by water depth (h) as functions of depth Froude number (Frh) and h, together with predictions from both methods, are presented in this paper. Finally, measures of the wave making energy efficiency of each pressure source, and the surfable quality of the waves generated by it, were developed and are presented.

Flow in a Centrifugal Fan Impeller at Off-Design Conditions

1984 ◽  
Vol 106 (4) ◽  
pp. 913-919 ◽  
Author(s):  
T. Wright ◽  
K. T. S. Tzou ◽  
S. Madhavan
Keyword(s):  
Three Dimensional ◽  
Internal Flow ◽  
Design Flow ◽  
Experimental Results ◽  
Surface Velocity ◽  
Scale Model ◽  
Valuable Insight ◽  
Centrifugal Fan ◽  
Viscous Effects ◽  
Element Analysis

Predicted and measured surface velocity and pressure distributions in the internal flow channels of a centrifugal fan impeller are presented for volume flow rates between 80 and 125 percent of design flow rate. Predictions are based on a fully three-dimensional, finite element analysis of the inviscid, incompressible blade channel flow. Additional predictions using a conventional quasi-three-dimensional analysis are presented for comparison. Experimental results were developed using extensive blade and sidewall surface pressure taps installed in a scale model of an airfoil-bladed centrifugal fan impeller designed for heavy industrial and power generation applications. The results illustrate the ability of both flow analyses to predict the dominant features of the impeller flow field, including peak blade surface velocities and adverse gradients at flows far from the design point. In addition, the experimental results provide valuable insight into the limiting channel diffusion values for typical centrifugal cascade performance, and the influence of viscous effects as seen in deviations from the ideal flow predictions.

A Novel Method for Generating Continuously Surfable Waves—Comparison of Predictions With Experimental Results

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Steven A. Schmied ◽  
Jonathan R. Binns ◽  
Martin R. Renilson ◽  
Giles A. Thomas ◽  
Gregor J. Macfarlane ◽  
...  
Keyword(s):  
Water Channel ◽  
Breaking Waves ◽  
Experimental Results ◽  
Stationary Waves ◽  
Ocean Engineering ◽  
Pressure Source ◽  
Circulating Water ◽  
Novel Method ◽  
The University ◽  
The Waves

In this paper, a novel idea to produce continuous breaking waves is discussed, whereby a pressure source is rotated within an annular wave pool, with the inner ring of the annulus having a sloping bathymetry to induce wave breaking. In order to refine the technique, work is being conducted to better understand the mechanics of surfable waves generated by moving pressure sources in restricted water. The pool aims to be capable of creating waves suitable for surfers from beginner to expert level, with an added benefit being by providing a safe learning environment, the overall surfing ability of the participants should be improved. The method of approach reported in this paper is the first stage of an experimental investigation of a novel method for generating continuously surfable waves utilizing a moving pressure source. The aim was to measure and assess the waves generated by two parabolic pressure sources and a wedge-shaped wavedozer (Driscoll, A., and Renilson, M. R., 1980, The Wavedozer. A System of Generating Stationary Waves in a Circulating Water Channel, University of Glasgow, Naval Architecture and Ocean Engineering, Glasgow, UK) for their suitability for future development of continuous breaking surfable waves. The tests were conducted at the University of Tasmania (UTas) Australian Maritime College (AMC) 100 m long towing tank. The predictions and experimental results for the wave height (H) at different values of depth Froude number (Frh) are presented in this paper. Finally, the preferred pressure source is determined based on the wave making energy efficiency and the quality of the waves for surfing.

Experimental and Numerical Aerodynamic Analysis of a Passenger Car: Influence of the Blockage Ratio on Drag Coefficient

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Armagan Altinisik ◽  
Emre Kutukceken ◽  
Habib Umur
Keyword(s):  
Wind Tunnel ◽  
Three Dimensional ◽  
Experimental Results ◽  
Scale Model ◽  
Passenger Car ◽  
Drag Coefficients ◽  
Drag Forces ◽  
Pressure Distributions ◽  
Numerical Studies ◽  
Blockage Correction

Experimental and numerical investigations were performed to determine the pressure distributions and the drag forces on a passenger car model. Experiments were carried out with 1/5th scale model FIAT Linea for 20% and ~ 1% blockage ratios in the Uludag University Wind Tunnel (UURT) and in the Ankara Wind Tunnel (ART), respectively. Computational fluid dynamics (CFD) analysis for 1/5th scale model with 0%, 5%, and 20% blockage ratios was performed to validate various blockage correction methods supplementary to the experimental results. Three-dimensional, incompressible, and steady governing equations were solved by STAR-CCM+ code with realizable k–ε two-layer turbulence model. The calculated drag coefficients were in good agreement with the experimental results within 6%. Pressure coefficients on the model surfaces have shown similar trends in the experimental and numerical studies. Some of the existing blockage correction methods were successfully compared in this study and predicted drag coefficients were within ± 5%. The authors propose the continuity and the Sykes blockage correction methods for passenger car models because they are very simple and practical and they can be used economically for engineering applications.

Three-dimensional Reconstruction of Microscopic Image Based on Multi-ST Algorithm

2020 ◽  
Vol 64 (2) ◽  
pp. 20506-1-20506-7
Author(s):  
Min Zhu ◽  
Rongfu Zhang ◽  
Pei Ma ◽  
Xuedian Zhang ◽  
Qi Guo
Keyword(s):  
3D Reconstruction ◽  
Three Dimensional ◽  
Scale Model ◽  
Microscopic Image ◽  
Multi Scale ◽  
Gaussian Pyramid ◽  
Cost Aggregation ◽  
Dimensional Reconstruction ◽  
Image Pairs ◽  
Accurate Matching

Abstract Three-dimensional (3D) reconstruction is extensively used in microscopic applications. Reducing excessive error points and achieving accurate matching of weak texture regions have been the classical challenges for 3D microscopic vision. A Multi-ST algorithm was proposed to improve matching accuracy. The process is performed in two main stages: scaled microscopic images and regularized cost aggregation. First, microscopic image pairs with different scales were extracted according to the Gaussian pyramid criterion. Second, a novel cost aggregation approach based on the regularized multi-scale model was implemented into all scales to obtain the final cost. To evaluate the performances of the proposed Multi-ST algorithm and compare different algorithms, seven groups of images from the Middlebury dataset and four groups of experimental images obtained by a binocular microscopic system were analyzed. Disparity maps and reconstruction maps generated by the proposed approach contained more information and fewer outliers or artifacts. Furthermore, 3D reconstruction of the plug gauges using the Multi-ST algorithm showed that the error was less than 0.025 mm.

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