scholarly journals Design and fabrication of wave generator using an oscillating wedge

2020 ◽  
Vol 3 (SI1) ◽  
pp. First
Author(s):  
Lu Thi Yen Vu ◽  
Ha Phuong ◽  
Ho Xuan Thinh ◽  
Dao Thanh Liem ◽  
Truong Quoc Thanh ◽  
...  
Keyword(s):  
Wave Height ◽  
Water Wave ◽  
Oscillation Amplitude ◽  
The Other ◽  
Data Logging ◽  
Desktop Computer ◽  
Small Ball ◽  
Wave Flume ◽  
Distance Sensor ◽  
The Waves

This paper describes the design and fabrication of a wave flume and associated equipment. The water wave generation by a triangle wedge is examined in this paper. Wave flume is fabricated by a concrete flume, which is 0.75-meter-wide, 1.3-meter-tall, and 11 meters long. One side of the flume is made of concrete, and the other side is made of clear mica sheets for observe the water wave profile. Wave flume is equipped with a triangle wedge located at one end of the wave flume, and this triangle wedge can be move along the rail of the wave flume. The passive wave absorber, which is made of honeycomb, which is located at the other end of the wave flume for absorbing energy waves generated from the wavemaker. The wedge is controlled by a desktop computer through Matlab software. The wedge can be controlled move up and down at a prescribed speed and oscillation amplitude corresponding to the desired wave height and wave frequency. At the middle flume is equipped microlaser distance sensor, which provides the data-logging capability. The microlaser distance sensor can collect wave height and wave period through a small ball, which is motioned in the tube, which is assembled on the water surface, and the small ball is very slight to avoid kinetic inertia energy. At the wavemaker is equipped with an Eccentricity Sensor, which is used to measure the wedge position to feedback for a desktop computer. Wave flume can generate the largest waves are about 0.2 meter high,  a period about 1 second, and a wavelength of about 1.5 meters. The waves generated by an oscillating wedge have been measured, analyzed to consider the generated wave energy.

scholarly journals Investigation of Wave Characteristics with Rotor Type Water Wave Generator

2017 ◽  
Vol 5 (2) ◽  
pp. 123-140
Author(s):  
Badhan Saha ◽  
Mazharul Islam ◽  
Abu Torab ◽  
Dewan Hasan Ahmed
Keyword(s):  
Water Wave ◽  
Wave Theory ◽  
Measuring Device ◽  
Wave Flume ◽  
Available Energy ◽  
Ac Motor ◽  
Type Water ◽  
The Waves ◽  
Rotor Type ◽  
Design Construction

Wave energy is the most available energy associated in deep water seas and oceans. Therefore, many attempts have been applied to capture these energies. This paper describes the design, construction and testing of water wave flume. The water wave flume contains an electromechanically driven rotor type wave maker to generate water wave powers. The waves are constructed by different sizes and arrangements of blades which are connected to the rotor. The rotor is driven by an ac motor to generate wave. At the end of the tank a force measuring device is attached opposite to the rotor to measure the thrust of the wave. Experimental results are validated with available literature and wave theory. The results also show that the width of the blade play major role in generating wave sizes including frequency, amplitude and the power. Wider blade displaces much water to generate wave but reduces the blade speed.

scholarly journals RELIABILITY OF PRESSURE SENSORS TO MEASURE WAVE HEIGHT IN THE SHOALING REGION

2018 ◽  
pp. 10 ◽  
Author(s):  
Massimiliano Marino ◽  
Iván Cáceres Rabionet ◽  
Rosaria Ester Musumeci ◽  
Enrico Foti
Keyword(s):  
Wave Height ◽  
Large Scale ◽  
Surf Zone ◽  
Transfer Functions ◽  
Pressure Sensors ◽  
Experimental Dataset ◽  
Wave Flume ◽  
Intermediate Waters ◽  
The Waves

A comparison between a range of transfer functions to recover wave height from pressure sensors data is presented. The analysis is carried out by means of a large-scale wave flume experimental dataset, in which resistive, acoustic and pressure gauges recovered wave height are compared as the waves travel from intermediate waters, to the shoaling region and finally into the surf zone. All the considered transfer functions result adequate in recovering wave height in intermediate waters, becoming gradually less accurate as the steepness of the wave increases in the shoaling region and in the surf zone. The accuracy of the compared transfer functions is assessed by means of an ensemble wave height based deviation.

Severe Wave Conditions at Sea

1971 ◽  
Vol 24 (3) ◽  
pp. 273-277 ◽  
Author(s):  
Laurence Draper
Keyword(s):  
Wave Height ◽  
North Sea ◽  
The Other ◽  
Sea Waves ◽  
Fixed Length ◽  
Southern North Sea ◽  
Wide Range ◽  
Casual Observer ◽  
The Waves ◽  
Vast Range

Perhaps the most surprising thing about sea waves is that they come in a vast range of shapes and sizes. The casual observer on a ship in waters not exposed to an ocean, for example the southern North Sea, may rightly think that the waves he can see have all been generated by the same wind blowing over some particular stretch of water for a fixed length of time. It then seems almost logical to deduce that all the waves ought to be of the same height, length and shape. Unfortunately this is not the case, the energy of sea waves is locked in wave components spread over a wide range of wave periods, each of which travels at a speed dictated by its period. Considering the very simple case of a sea with only wave components, when a crest of one component overtakes the other, a higher wave will ensue. As a result of this process, high waves come in groups; during the time in which the components gradually get into phase the wave height builds up giving a train of waves of increasing, which then decreases as the faster component travels away, until when they are out of phase the sea is temporarily fairly calm. This is the reason why it is commonly said that every seventh wave is the highest, although whether it is every fourth or every fourteenth depends on the relative speeds of the components.

Kajian Model Fisik Pengaruh Freeboard dan Susunan Buis Beton Sebagai Pemecah Gelombang Tenggelam Ambang Rendah (Pegar) Dalam Mereduksi Gelombang

2017 ◽  
Vol 1 (2) ◽  
pp. 34
Author(s):  
Zulkarnain Zulkarnain ◽  
Nadjadji Anwar
Keyword(s):  
Low Cost ◽  
Relative Depth ◽  
Submerged Breakwater ◽  
Wave Flume ◽  
Concrete Cylinder ◽  
Engineering Department ◽  
Sea Area ◽  
The Waves ◽  
Transmission Test ◽  
Better Than

The Research Center and Development of Water (Puslitbang) is currently developing the Submerged Breakwater in shallow sea area (PEGAR). The author is interested to examine the material that easily obtained in the field of RCP concrete cylinder. The observation is how it to be ability in function as submerged breakwater an go green and low cost. The physical model of wave transmission test is how the response to the structure in ability to damping of wave as the breakwater function. In this research breakwater used is submerged breakwater type by using concrete cylinder (buis beton). The purpose from this research is to know how the response of breakwater structure to the waves through it, with some variation of the structure by creating a structure with three variations of the arrangement and freeboard that is the relative depth with the crest width is constant. The wave generated test in this study is using regular waves in wave flume at FTSP Civil Engineering Department of Institute Technology Ten November. From the analysis of the effect of the installation of submerged breakwater by using concrete cylinder to the wave damping value, it can be concluded that the factors that are very influential is the freeboard and the composition of concrete cylinder. Scenario A (rigid vertical massive) is capable of producing the smallest value of kt is 0.33. As for scenario B (rigid horyzontal massive) with a damping value of 0.5, while the scenario C (rigid permeable) is only able to produce kt value of 0.71. Scenario A is better than scenario B and C Because the position of arrangement of A is very good used to damp wave in small or big freeboard conditions.

Experimental Research on Damages Detection of Pipeline Structure by Using PZT-Based Waves

2011 ◽  
Author(s):  
Shi Yan ◽  
Binbin He ◽  
Naizhi Zhao
Keyword(s):  
Damage Detection ◽  
Lead Zirconate Titanate ◽  
Smart Materials ◽  
Arrival Time ◽  
Mode Conversion ◽  
Guided Wave ◽  
The Other ◽  
Damage Location ◽  
The Waves ◽  
Peak Value

Pipeline structure may generate damages during its service life due to the influence of environment or accidental loading. The damages need to be detected and repaired if they are severe enough to influence the transportation work. Non-destructive detection using smart materials combined with suitable diagonal algorithms are widely used in the field of structural health monitoring (SHM). Piezoelectric ceramics (such as Lead Zirconate Titanate, PZT) is one of the smart materials to be applied in the SHM due to the piezoelectric effect. So far, the PZT-based wave method is widely used for damage detection of structures, in particular, pipeline structures. A series of piezoelectric patches are bonded on the surface of the pipeline structure to monitor the damages such as local crack or effective area reduction due to corrosion by using diagonal waves. The damage of the pipeline structure can be detected by analysis of the received diagonal waves which peak value, phase, and arriving time can be deferent from the health ones. The response of the diagonal wave is not only correlated to the damage location through estimation of the arrival time of the wave peak, but also associated with the peak value of the wave for the reduction of wave energy as the guided wave passing through the damages. Therefore, the presence of damages in the pipeline structure can be detected by investigating the parameter change of the guided waves. The change of the wave parameters represents the attenuation, deflection and mode conversion of the waves due to the damages. In addition, the guided wave has the ability of quick detecting the damage of the pipeline structure and the simplicity of generating and receiving detection waves by using PZT patches. To verify the proposed method, an experiment is designed and tested by using a steel pipe bonded the PZT patches on the surface of it. The PZT patches consist of an array to estimate the location and level of the damage which is simulated by an artificial notch on the surface of the structure. The several locations and deep heights of the notches are considered during the test. A pair of the PZT patches are used at the same time as one is used as an actuator and the other as a sensor, respectively. A tone burst of 5 cycles of wave shape is used during the experiment. A wave generator is applied to create the proposed waves, and the waves are amplified by an amplifier to actuate the PZT patch to emit the diagonal waves with appropriately enough energy. Meanwhile, the other PZT patch is used as a sensor to receive the diagonal signals which contain the information of the damages for processing. For data processing, an index of root mean square deviation (RMSD) of the received data is used to estimate the damage level by compare of the data between the damaged and the health peak valves of the received signals. The time reversal method which aimed at increasing the efficiency of the detection is also used to detect the damage location by estimating the arrival time of the reflected wave passing with a certain velocity. The proposed method experimentally validates that it is effective for application in damage detection of pipeline structure.

scholarly journals Wave Breaking in Undular Bores with Shear Flows

Water Waves ◽  
2021 ◽  
Author(s):  
Maria Bjørnestad ◽  
Henrik Kalisch ◽  
Malek Abid ◽  
Christian Kharif ◽  
Mats Brun
Keyword(s):  
Turbulent Flows ◽  
Wave Breaking ◽  
Vries Equation ◽  
Kdv Equation ◽  
Flow Depth ◽  
Present Contribution ◽  
Undular Bore ◽  
Wave Flume ◽  
The Kdv Equation ◽  
The Waves

AbstractIt is well known that weak hydraulic jumps and bores develop a growing number of surface oscillations behind the bore front. Defining the bore strength as the ratio of the head of the undular bore to the undisturbed depth, it was found in the classic work of Favre (Ondes de Translation. Dunod, Paris, 1935) that the regime of laminar flow is demarcated from the regime of partially turbulent flows by a sharply defined value 0.281. This critical bore strength is characterized by the eventual breaking of the leading wave of the bore front. Compared to the flow depth in the wave flume, the waves developing behind the bore front are long and of small amplitude, and it can be shown that the situation can be described approximately using the well known Kortweg–de Vries equation. In the present contribution, it is shown that if a shear flow is incorporated into the KdV equation, and a kinematic breaking criterion is used to test whether the waves are spilling, then the critical bore strength can be found theoretically within an error of less than ten percent.

scholarly journals Experimental investigation of vertical and horizontal reinforcement geotextiles in forest road pavement

2018 ◽  
Vol 64 (No. 7) ◽  
pp. 296-302 ◽  
Author(s):  
Dini Morteza ◽  
Nikooy Mehrdad ◽  
Naskovets Michael Trofimovich ◽  
Ghomi Alireza
Keyword(s):  
Experimental Investigation ◽  
The Other ◽  
Data Logging ◽  
Truck Traffic ◽  
Horizontal Structure ◽  
Forest Road ◽  
Vehicle Traffic ◽  
Road Pavement ◽  
Significant Difference ◽  
Experimental Survey

In this research, the results of an experimental survey on the measurement of vertical stresses are presented. Four treatments were used in this study such as combination of geotextile vertical and horizontal structure with dimensions of 5 × 5 and 10 × 10 cm, horizontal geotextile and the treatment without geotextile. Five sensors were installed in different hole locations and the lead of the truck traffic was transmitted by cables to data logging and recording devices to measure the pressure from vehicle traffic on the simulated pavement layer. Mean comparison of the treatments showed that the geotextile with vertical and horizontal structure and dimensions of 5 × 5 cm exerted the lowest pressure on the lower layers compared with the other treatments and there was a significant difference between the value of this treatment and the other treatments and that this treatment could significantly reduce the pressure of truck traffic on the forest road.

Marguerite Yourcenar, traductrice

Babel ◽  
1994 ◽  
Vol 40 (1) ◽  
pp. 21-37
Author(s):  
Ivo R.V. Hoefkens
Keyword(s):  
The Other ◽  
Political Sphere ◽  
Negro Spirituals ◽  
Marguerite Yourcenar ◽  
Other Hand ◽  
The Aesthetic ◽  
Literary Output ◽  
Ethical Communication ◽  
The Waves ◽  
Second Period

Marguerite Yourcenar, known as an author, is also the translator of about a dozen works. My purpose here is to trace the evolution of her oeuvre in the field of translation in relation to her literary output. I have divided the former into three distinct periods, the first of which covers the closing years of the 1930s, when Marguerite Yourcenar translated Virginia Woolf's The Waves and Henry James's What Maisie Knew. Her interest in these authors is to a large extent stylistic. On the other hand, the translation of Constantin Cavafy's poetry, which was begun during the same period, reflects the intimist themes to be found in Marguerite Yourcenar's early narratives {Alexis and the others), although she was then already seeking out other thematic sources. The translation was only published in 1958. It consequently falls within a second period: that of the "présentations critiques" (critical commentaries). These major efforts in translation {Présentation critique de Constantin Cavafy, La Couronne et la Lyre, Fleuve profonde, Sombre rivière) are marked by a manifest preoccupation with the aesthetic. But themes of a more universal character and engagement in the socio-political sphere also enter into the choice of the texts for translation (negro spirituals, Présentation critique d'Hortense Flexner). These translations were contemporaneous with the creation of Marguerite Yourcenar's most important novels, namely Mémoires d'Hadrien and L'OEuvre au Noir. The last of the three periods, the 1980s, finds her tackling far less ambitious projects, the function of which tends increasingly towards ethical communication. The only one of them that bears any resemblance to the "présentations critiques" is the essay on Yukio Mishima and the translation of Cinq Nô Modernes, assuming that these are to be considered as an ensemble. Here, as elsewhere, it also emerges that Marguerite Yourcenar is largely indifferent to the existence of other translations.

An experimental investigation of the nature and origin of microseisms at St. Louis, Missouri

1940 ◽  
Vol 30 (2) ◽  
pp. 139-178
Author(s):  
J. Emilio Ramirez
Keyword(s):  
Wave Length ◽  
Vertical Axis ◽  
The Other ◽  
Wave Form ◽  
Stationary Waves ◽  
Retrograde Motion ◽  
Time Signals ◽  
Group Form ◽  
Triangular Network ◽  
The Waves

Summary Over a period of six months, from July to December, 1938, an investigation on microseismic waves has been carried out in the Department of Geophysics of St. Louis University. Four electromagnetic seismographs, specially designed for recording microseisms, were installed in the city of St. Louis in the form of a triangular network. Two of these were E-W components, one at the St. Louis University Gymnasium and the other 6.4 km. due west at Washington University. The other two were arranged as N-S components, one at the St. Louis University Gymnasium and one 6.3 km. due south at Maryville College. The speed of the photographic paper was 60 mm/min., and time signals were recorded automatically and simultaneously on each paper from the same clock every minute and at shorter intervals from a special pendulum and “tickler” combination by means of telephone wires. The results have demonstrated beyond doubt that microseismic waves are traveling and not stationary waves. The same waves have been identified at each one of the stations of the network, and also at Florissant, 21.8 km. away from St. Louis University. The speed of microseismic waves at St. Louis was determined from several storms of microseisms and it was found to be 2.67±0.03 km/sec. The direction of microseisms was also established for most of the storms and it was found that about 80 per cent of incoming microseisms at St. Louis were from the northeast quadrant during the interval from July to December, 1938. No microseisms were recorded from the south, west, or southwest. The period of the waves varied between 3.5 and 7.5 sec. The average period was about 5.4 sec. The microseismic wave length was therefore of the order of 14¼ km. A study of the nature of microseismic waves from the three Galitzin-Wilip components of the Florissant station reveals in the waves many of the characteristics of the Rayleigh waves; that is, the particles in the passage of microseismic waves move in elliptical orbits of somewhat larger vertical axis and with retrograde motion. A comparison carried over a period of more than a year between microseisms and microbarometric oscillations recorded by specially designed microbarographs showed no direct relationship between the two phenomena in wave form, group form, period, or duration of storms. The source of microseisms is to be found not over the land, but rather out over the surface of the ocean. The amplitudes of microseisms depend only on the intensity and widespread character of barometric lows traveling over the ocean. Several correlations between the two phenomena seem to make this conclusion rather evident. Special emphasis is laid on the fact that all the determined directions of incoming microseisms at St. Louis point to a deep barometric low over the ocean. The period of microseisms seems to be a function of the distance between the station and the source of microseisms. The exact mechanism by which barometric lows over the ocean water result in the production of microseisms needs further investigation. Large microseisms have been produced without any indication of surf near the coasts, or with winds blowing from the land toward the ocean.

Transverse dam-break waves

2014 ◽  
Vol 758 ◽  
Author(s):  
S. Karimpour Ghannadi ◽  
Vincent H. Chu
Keyword(s):  
Froude Number ◽  
Flow Rate ◽  
Main Flow ◽  
Dam Break ◽  
The Other ◽  
Water Diversion ◽  
The Family ◽  
The One ◽  
Limiting Case ◽  
The Waves

AbstractNumerical simulations of the transverse dam-break waves (TDWs) produced by the sudden removal of a gate on the side of a waterway are conducted based on the shallow-water equations to find solutions to a family of water-diversion problems. The Froude numbers in the main flow identify the members of the family. The depth and discharge profiles are analysed in terms of Ritter’s similarity variable. For subcritical main flow, the waves are comprised of a supercritical flow expansion followed by a subcritical outflow. For supercritical main flow, on the other hand, the waves are analogous to the Prandtl–Meyer expansion in gas dynamics. The diversion flow rate of two-dimensional TDWs on a flat bed is 55 % greater than the one-dimensional flow rate of Ritter in the limiting case of zero main flow, and approaches the rate of Ritter in the other limit when the value of the Froude number in the main flow approaches infinity. The diversion flow rate over a weir is generally higher than the rate over a flat bed depending on the Froude number of the main flow. These numerical simulation results are consistent with laboratory observations.

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