scholarly journals Planar Installation Characteristics of Crown Depth-Variable Artificial Coral Reef on Improving Coastal Resilience: A 3D Large-Scale Experiment

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1526
Author(s):  
Sunghoon Hong ◽  
Seungil Baek ◽  
Yeonjoong Kim ◽  
Jooyong Lee ◽  
Adi Prasetyo ◽  
...  
Keyword(s):  
Coral Reef ◽  
Large Scale ◽  
Profile Analysis ◽  
Three Dimensional ◽  
Tracer Experiment ◽  
Beach Erosion ◽  
Beach Profile ◽  
Submerged Breakwater ◽  
Coastal Resilience ◽  
Scale Experiment

Coastal resilience has received significant attention for managing beach erosion issues. We introduced flexible artificial coral reef (ACR) structures to diminish coastal erosion, but planar installation effects should be considered to evaluate the feasibility of coastline maintenance. In this study, we conducted a three-dimensional large-scale experiment to investigate the characteristics of planar installation of ACR, focusing on the wave mitigation performance, wave profile deformation with delay, nearshore current movement, deposition and erosion trends, and beach profile variation. We found that the ACR diminished the wave height by ~50% and the current intensity by ~60% compared with that of a conventional submerged breakwater made of dolos units. Using the dispersion velocity of the dye in a tracer experiment, the dispersion time of the ACR was approximately 1.67-times longer than that of the dolos and the current velocity was reduced, revealing that ACR significantly reduced structural erosion. With dolos, severe erosion of >10 cm occurred behind the structure, whereas there was only slight erosion with the ACR. Moreover, in a vertical beach-profile analysis, the ACR exhibited greater shoreline accretion than that of dolos. These results indicate the potential of ACR in improving coastal resilience.

scholarly journals Improved Coastal Erosion Prevention Using a Hybrid Method with an Artificial Coral Reef: Large-Scale 3D Hydraulic Experiment

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2801
Author(s):  
Taeyoon Kim ◽  
Seungil Baek ◽  
Yongju Kwon ◽  
Jooyong Lee ◽  
Sung Min Cha ◽  
...  
Keyword(s):  
Coral Reef ◽  
Hybrid Method ◽  
Coastal Erosion ◽  
Large Scale ◽  
Local Scour ◽  
Return Flow ◽  
Structural Failure ◽  
Submerged Breakwater ◽  
Sediment Transportation ◽  
Erosion Mitigation

Coastal erosion, a worldwide social issue, has garnered substantial attention. Numerous methods have been implemented to control coastal erosion problems; however, the presence of rigid structures limits erosion mitigation, thereby causing various challenges. For instance, in the case of submerged breakwaters, local scour in front of the structure and scour caused by the flow occurring in open inlets affect the subsidence and stability of the structure and can also cause structural failure. To solve these problems, this paper proposes a hybrid method of using a submerged breakwater with an artificial coral reef installation; further, this study evaluates the attenuation of waves and mitigation of sediment transportation through large-scale 3D hydraulic experiments. We found that the hybrid method with an artificial coral reef installed in the open inlet shows excellent wave control and plays a clearly beneficial role in the advancement of the shoreline. The artificial coral reef method reduced the return flow generated by the drag force at the breakwater shoulder and open inlet. In addition, scour at the breakwater shoulder was inhibited by collecting the sand escaping offshore. Simultaneously, scour at the open inlet was also mitigated. The application of the hybrid method compensated for the problems caused by local scour and erosion in the submerged breakwater, thereby leading to the improvement of its function. Therefore, the hybrid method proposed in this paper was determined to be applicable not only for submerged breakwaters, but also for various structures for controlling coastal erosion.

An Experimental Investigation of the Flow Through an Axial-Flow Pump

1995 ◽  
Vol 117 (3) ◽  
pp. 485-490 ◽  
Author(s):  
W. C. Zierke ◽  
W. A. Straka ◽  
P. D. Taylor
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Axial Flow ◽  
Fast Response ◽  
Complex Flow ◽  
Penn State ◽  
Response Pressure ◽  
Axial Flow Pump ◽  
Scale Experiment ◽  
High Reynolds

The high Reynolds number pump (HIREP) facility at ARL Penn State has been used to perform a low-speed, large-scale experiment of the incompressible flow of water through a two-blade-row turbomachine. The objectives of this experiment were to provide a database for comparison with three-dimensional, turbulent flow computations, to evaluate engineering models, and to improve our physical understanding of many of the phenomena involved in this complex flow field. This summary paper briefly describes the experimental facility, as well as the experimental techniques—such as flow visualization, static-pressure measurements, laser Doppler velocimetry, and both slow- and fast-response pressure probes. Then, proceeding from the inlet to the exit of the pump, the paper presents highlights of experimental measurements and data analysis, giving examples of measured physical phenomena such as endwall boundary layers, separation regions, wakes, and secondary vortical structures. In conclusion, this paper provides a synopsis of a well-controlled, larger scope experiment that should prove helpful to those who wish to use the database.

Erosion Mitigation Using Submerged Breakwater Composed of Artificial Reefs

2015 ◽  
Vol 744-746 ◽  
pp. 1171-1174
Author(s):  
Kyu Han Kim ◽  
Bum Shick Shin
Keyword(s):  
Wave Attenuation ◽  
Three Dimensional ◽  
Artificial Reef ◽  
Beach Erosion ◽  
Artificial Reefs ◽  
Return Flow ◽  
Two Dimensional ◽  
Submerged Breakwater ◽  
Erosion Mitigation ◽  
Study Offer

In this study, erosion mitigation by submerged breakwater with artificial reefs is investigated among other means of countermeasures. Beach erosion mechanism near the submerged breakwater and the performance of artificial reef blocks are analyzed in the laboratory. Two-dimensional and three-dimensional laboratory experiments are applied to the analysis. The results of two-dimensional experiments prove that new artifi-cial blocks showed a better performance than the existing blocks in terms of wave attenuation due to wave breaking turbulence near the crest of the structure. Three-dimensional experiments show reduced return flow velocity by half by installing another type of new artificial block in between submerged breakwaters. Return flow has been creating vulnerability in countermeasures by submerged breakwater. Therefore, artifi-cial reef blocks suggested by this study offer solutions to the existing mitigation problems with submerged breakwater.

scholarly journals ANALYSIS ON PERFORMANCE OF THE EMERGENCY NOURISHMENT PROJECT AT WEST BEACH OF BEIDAIHE, CHINA

2011 ◽  
Vol 1 (32) ◽  
pp. 98 ◽  
Author(s):  
Yanxiong Yang ◽  
Jiabo Zhang ◽  
Cuiping Kuang ◽  
Yu Zhang ◽  
Lulu He ◽  
...  
Keyword(s):  
Water Conservation ◽  
Large Scale ◽  
Beach Nourishment ◽  
Beach Erosion ◽  
Profile Measurement ◽  
Beach Profile ◽  
Survey Period ◽  
Before And After ◽  
Conservation Projects ◽  
Large Scale Project

Beach erosion is prevalent on China’s 18,000 km-long coastline, which has been aggravating due to urban development, river-damming and soil and water conservation projects since late 1970s. Beach erosion threatens the health of beaches of bathing places throughout the world. An effective way to defense the beach erosion is beach nourishment. In this paper, the study on an experimental beach nourishment project, which was conducted to provide data and experience for a large-scale project, was detailed. Field survey was conducted to study the performance of the project. Before and after the project, 8 monitoring profiles had been kept measuring along with the berm positions. The beach profile measurement indicates that after a little retreat the beach got relatively equilibrium, while the berm measurement shown a broadened intertidal zone getting stable eventually. In a word, the filled beach was eroded a little but finally got relatively stable in the survey period.

scholarly journals LONG TERM PERFORMANCE OF A SUBMERGED COASTAL CONTROL STRUCTURE: A CASE STUDY OF THE NARROWNECK MULTI-FUNCTIONAL ARTIFICIAL REEF

2012 ◽  
Vol 1 (33) ◽  
pp. 54 ◽  
Author(s):  
Angus Jackson ◽  
Rodger Tomlinson ◽  
Bobbie Corbett ◽  
Darrell Strauss
Keyword(s):  
Large Scale ◽  
Control Point ◽  
Artificial Reef ◽  
Beach Erosion ◽  
Gold Coast ◽  
Storm Events ◽  
Marine Habitat ◽  
Submerged Breakwater ◽  
Long Term Performance ◽  
Term Performance

In response to the increasing occurrences of beach erosion along Surfers Paradise and Main Beaches - Gold Coast, Australia, the Northern Gold Coast Beach Protection Strategy [NGCBPS] was developed to widen the beach by 20-30m as well as improving surfing conditions as a secondary objective. The strategy, implemented in 1999- 2000, involved large-scale beach nourishment and construction of a submerged breakwater “reef” to act as a control point at Narrowneck. Construction of the reef involved innovative filling and placement methods using very large sand filled geotextile containers coupled with significant advances with regards to design of the geotextile material and containers. In the 11 years since construction, there has been substantial monitoring of the project since its completion in late 2000 including: - video imaging using webcams; hydrographic and beach surveys; aerial and oblique photography; surf and surf safety observations and GPS surfing track plots; and geotextile container condition and stability. This paper presents an update on the performance of the reef over the last four years. In particular, the response of the structure and the shoreline to a series of major storm events in 2009 has been examined. The results have shown that the erosion caused by these major events was accommodated within the wider beach created in 1999. Over the next 2 years there was a gradual recovery in the lee of the reef with a subtle groyne effect resulting in an even larger increase in the width of the updrift beach. A detailed underwater condition survey was also undertaken in 2011, to determine changes in the condition of the geotextile containers. This revealed a number of containers missing or damaged, and that seaward containers were covered by sand. The marine habitat which has been a feature of the reef has been impacted by the increased coverage of sand, but still shows high abundance and biodiversity.

scholarly journals BEACH EROSION COUNTERMEASURE USING NEW ARTIFICIAL REEF BLOCKS

2012 ◽  
Vol 1 (33) ◽  
pp. 107 ◽  
Author(s):  
Kyuhan Kim ◽  
Sungwon Shin ◽  
Chongkun Pyun ◽  
Hyun Dong Kim ◽  
Nobuhisa Kobayashi
Keyword(s):  
Wave Breaking ◽  
Laboratory Experiments ◽  
Wave Attenuation ◽  
Three Dimensional ◽  
Artificial Reef ◽  
Beach Erosion ◽  
Return Flow ◽  
Two Dimensional ◽  
Flow Mechanism ◽  
Submerged Breakwater

Two-dimensional and three-dimensional laboratory experiments were conducted to investigate not only the flow mechanism near the submerged breakwater but the performance of two newly developed eco-friendly artificial reef blocks. The results of two-dimensional experiments proved that new artificial blocks (EREEB) showed a better performance than TTP in terms of wave attenuation due to wave breaking turbulence near the crest of the structure. Three-dimensional experiments convinced that installing another type of new artificial block (WERF) in between submerged breakwater reduced the return flow velocity more than 50% compared with the gap between the breakwaters is empty. Therefore, these two types of newly developed artificial reef block can contribute the counter measure of beach erosion and habitat of sea lives.

scholarly journals HYDRAULIC APPROACH TO SHORELINE CHANGE DUE TO SUBMERGED BREAKWATER

2020 ◽  
pp. 40
Author(s):  
Inho Kim ◽  
Hyungseok Lee ◽  
Jinhoon Kim ◽  
Sungyeol Chang
Keyword(s):  
Numerical Analysis ◽  
Shoreline Change ◽  
Beach Erosion ◽  
Rip Current ◽  
Rip Currents ◽  
Induced Current ◽  
Beach Profile ◽  
Submerged Breakwater ◽  
Sand Movement ◽  
Wave Induced

The items of investigation include wave induced current, wave height, beach profile, shoreline change, etc. The investigation has been performed seasonally. After the construction of submerged breakwaters, a tombolo was generated behind the submerged breakwaters. This caused beach erosion in the nearby areas. Rip currents are mainly generated near submerged breakwaters, which plays a role in the transportation of sand in the offshore direction. In order to analyze the sand movement, numerical analysis was conducted. The analysis indicated that a strong rip current is generated near submerged breakwaters.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/5p2wiNSMKlM

scholarly journals A Review on Additive Manufacturing Possibilities for Electrical Machines

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1940
Author(s):  
Muhammad Usman Naseer ◽  
Ants Kallaste ◽  
Bilal Asad ◽  
Toomas Vaimann ◽  
Anton Rassõlkin
Keyword(s):  
Additive Manufacturing ◽  
Large Scale ◽  
Three Dimensional ◽  
Electrical Machines ◽  
Electromagnetic Properties ◽  
Scale Production ◽  
Performance Parameters ◽  
Large Scale Production ◽  
One Step ◽  
Manufacturing Techniques

This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

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