Pre-Stress of Underwater Flextensional Transducers and Its Variation with Water Depth

2008 ◽  
Vol 94 (3) ◽  
pp. 483-486
Author(s):  
He Xiping ◽  
Ren Huijuan
Keyword(s):  
Water Depth ◽  
Flextensional Transducers

Comparison of the performance of oscillating water column devices based on arrangements of water columns

2020 ◽  
Vol 14 (3) ◽  
pp. 7082-7093
Author(s):  
Jahirwan Ut Jasron ◽  
Sudjito Soeparmani ◽  
Lilis Yuliati ◽  
Djarot B. Darmadi
Keyword(s):  
Wave Propagation ◽  
Water Column ◽  
Water Depth ◽  
Graphical Form ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Power Absorption ◽  
Water Columns ◽  
Single Column ◽  
Parallel Arrangement

The hydrodynamic performance of oscillating water column (OWC) depends on the depth of the water, the size of the water column and its arrangement, which affects the oscillation of the water surface in the column. An experimental method was conducted by testing 4 water depths with wave periods of 1-3 s. All data recorded by the sensor is then processed and presented in graphical form. The research focused on analyzing the difference in wave power absorption capabilities of the three geometric types of OWC based on arrangements of water columns. The OWC devices designed as single water column, the double water column in a series arrangement which was perpendicular to the direction of wave propagation, and double water column in which the arrangement of columns was parallel to the direction of wave propagation. This paper discussed several factors affecting the amount of power absorbed by the device. The factors are the ratio of water depth in its relation to wavelength (kh) and the inlet openings ratio (c/h) of the devices. The test results show that if the water depth increases in the range of kh 0.7 to 0.9, then the performance of the double chamber oscillating water column (DCOWC) device is better than the single chamber oscillating water column (SCOWC) device with maximum efficiency for the parallel arrangement 22,4%, series arrangement 20.8% and single column 20.7%. However, when referring to c/h, the maximum energy absorption efficiency for a single column is 27.7%, double column series arrangement is 23.2%, and double column parallel arrangement is 29.5%. Based on the results of the analysis, DCOWC devices in parallel arrangement showed the ability to absorb better wave power in a broader range of wave frequencies. The best wave of power absorption in the three testing models occurred in the wave period T = 1.3 seconds.

A Study of the Average Flow in Open Channel with Baffle Blocks Distributed Uniformly

10.29007/zx1w ◽  
2018 ◽  
Author(s):  
Dung Tien Tran ◽  
Anh Tuan Le ◽  
Hong Nhung Le ◽  
Viet Hung Ho
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Open Channel ◽  
Block Size ◽  
Average Flow ◽  
Modelling Studies ◽  
Baffle Block

A study of average flow in open channel with baffle blocks distributed uniformly has been considered by using channel with varied slopes. In this article, experimental and modelling studies were introduced when the correlation between the water depth and baffle block size is significant. The objective of the work is to give the rudimentary relations between discharge and water level in the channels. When the water depth is large, the effect of bottom channel friction on the flow is relatively small. This paper also gives applications of the software ‘Telemac-2D’ to simulate the flow under different conditions.

PENDUGAAN EROSI DAN NERACA AIR EMBUNG DI WILAYAH PERBATASAN KABUPATEN BELU NUSA TENGGARA TIMUR

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Wahyu Widiyono
Keyword(s):  
Water Balance ◽  
Water Resource ◽  
Water Depth ◽  
Rainy Season ◽  
Water Reservoir ◽  
Water Shortage ◽  
Regional Government ◽  
Environment Management ◽  
Individual Number ◽  
Rainfall Volume

Embung as a man made water reservoir is one of methods to overcome the water shortage in the border area, Belu District, East Nusa Tenggara Province. A number of 27 embungs were built by Regional Government in this area. Embung water and environment management is the main problem to sustain water resource. The research to inventory and identify of vegetation, to predict erosion, to monitor water balance, and to optimize water utilization were conducted, in 2005-2008. The research was undertaken in Embung Leosama. Methods were survey, observation, monitoring and analysis. Results were: (1). There were 7 species and 90 individual number of tree; (2). Prediction of erosion was 97.383 ton/ha/year; (3). Water depth as indicator of embung water balance was decrease due to a little rainfall volume in rainy season 2006/2007; but it was increase in 2007/2008; (4). Embung water can be optimized for drinking cattle, horticulture, nursery and regreening irrigation.Key Words: embung, erosion, water balance.

Effect of Water Depth on Nitrogen Use Efficiency and Nitrogen‐15 Balance in Lowland Rice 1

1987 ◽  
Vol 79 (2) ◽  
pp. 210-216 ◽  
Author(s):  
S. K. De Datta ◽  
W. N. Obcemea ◽  
R. Y. Chen ◽  
J. C. Calabio ◽  
R. C. Evangelista
Keyword(s):  
Water Depth ◽  
Nitrogen Use Efficiency ◽  
Lowland Rice ◽  
Nitrogen Use ◽  
Effect Of Water ◽  
Use Efficiency

scholarly journals Effect of water flow and depth on fatigue crack growth rate of underwater wet welded low carbon steel SS400

2021 ◽  
Vol 11 (1) ◽  
pp. 329-338 ◽  
Author(s):  
E. Surojo ◽  
J. Anindito ◽  
F. Paundra ◽  
A. R. Prabowo ◽  
E. P. Budiana ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Carbon Steel ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Water Flow ◽  
Water Depth ◽  
Water Flow Rate ◽  
Low Carbon Steel ◽  
Low Carbon

Abstract Underwater wet welding (UWW) is widely used in repair of offshore constructions and underwater pipelines by the shielded metal arc welding (SMAW) method. They are subjected the dynamic load due to sea water flow. In this condition, they can experience the fatigue failure. This study was aimed to determine the effect of water flow speed (0 m/s, 1 m/s, and 2 m/s) and water depth (2.5 m and 5 m) on the crack growth rate of underwater wet welded low carbon steel SS400. Underwater wet welding processes were conducted using E6013 electrode (RB26) with a diameter of 4 mm, type of negative electrode polarity and constant electric current and welding speed of 90 A and 1.5 mm/s respectively. In air welding process was also conducted for comparison. Compared to in air welded joint, underwater wet welded joints have more weld defects including porosity, incomplete penetration and irregular surface. Fatigue crack growth rate of underwater wet welded joints will decrease as water depth increases and water flow rate decreases. It is represented by Paris's constant, where specimens in air welding, 2.5 m and 5 m water depth have average Paris's constant of 8.16, 7.54 and 5.56 respectively. The increasing water depth will cause the formation of Acicular Ferrite structure which has high fatigue crack resistance. The higher the water flow rate, the higher the welding defects, thereby reducing the fatigue crack resistance.

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