scholarly journals PRESSURE DISTRIBUTIONS ON A VERTICAL BREAKWATER: EXPERIMENTAL

2011 ◽  
Vol 1 (32) ◽  
pp. 24 ◽  
Author(s):  
Dulce Maria Perez ◽  
Mariana Correa ◽  
Miguel Ortega ◽  
María Clavero ◽  
Miguel Angel Losada
Keyword(s):  
Wave Height ◽  
Wave Length ◽  
Pressure Variation ◽  
Relative Height ◽  
Rectangular Section ◽  
Uplift Pressure ◽  
Wave Flume ◽  
Pressure Distributions ◽  
Total Wave ◽  
Run Up

This work studies the horizontal and uplift pressure distributions over a caisson founded on porous materials, and their dependence on the stone diameter and the height of the foundation. For this, tests at a wave flume with an idealized composite breakwater of rectangular section, varying the depth of the foundation of the caisson and the diameter of the stones, were carried on. Eight resistive gauges and eight pressures sensors were used to measure free surface elevations and horizontal and uplift pressure variation, respectively. Results show that: 1) there exist a “saturation” of the reflection coefficient for B/L>0.4, being B the width of the dike and L the wave length, 2) by using the total wave height measured at the toe of the dike in the analysis, the dispersion of the results is significantly reduced; 3) dimensionless run-up and pressures obtained using total wave height mainly depends on the reflection regime and on the relative height of the foundation; 4) maximum uplift and horizontal forces are not always in phase, and three regimes are identified depending on which force dominates; and 5) the relation between the dimensionless forces with the total wave height at the toe of the dike depends mainly on the reflection regime and on the relative foundation height.

scholarly journals Analisa Perhitungan Analitik dan Data Eksperimen Parameter Gelombang pada Wave Flume dengan Wavemaker Tipe Piston

2017 ◽  
Vol 20 (1) ◽  
pp. 30
Author(s):  
Alfi Satriadi ◽  
Sugeng Widada ◽  
Harmon Prayogi
Keyword(s):  
Experimental Data ◽  
Wave Height ◽  
Wave Length ◽  
Physical Modelling ◽  
Ocean Waves ◽  
Dimensionless Number ◽  
Relative Depth ◽  
Model Bias ◽  
Wave Flume ◽  
External Forces

Ocean waves is one of the ocean phenomenon and It is occurred by the external forces. There are some approaches to study this phenomenon which are analytical, numerical, and physical modelling. This research aims to compare between analytical and experimental data. The methods were used in the research divided into three steps. First step was calculating theoretical equation of the relationship between dimensionless number of relative depth (kh) and stroke and wave height ratio (H/S). Secondly, the wave parameters including wave height (H), water depth (d), and wave length (L) were measured in a wave flume. Finally, the value of percentage model bias (PB) was calculated. It showed at 15,513% and 8,5% for 50 rpm and 80 rpm, respectively. In conclusion based on PB, experimental data had positive correlation to analytical equation. Keywords: Waves, piston type wavemaker, percentage model bias (PB)  Gelombang merupakan salah satu fenomena yang ada di laut. Dalam mempelajari fenomena ini dilakukan berbagai pendekatan diantaranya pendekatan analitik, pemodelan numerik, dan pemodelan fisik. Penelitian ini hanya mengkaji hasil perhitungan analitik dan data eksperimen menggunakan wavemaker tipe piston berdasarkan nilai percentage model bias (PB). Metode yang dilakukan merupakan metode kuantitatif yang dibagi menjadi tiga tahap. Tahap pertama melakukan perhitungan berdasarkan persamaan analitis hubungan antara bilangan tak berdimensi kedalaman relatif (kh) dan rasio antara tinggi gelombang dan panjang stroke (H/S). Tahap kedua adalah melakukan pengukuran parameter gelombang yaitu tinggi gelombang (H), kedalaman (d), dan panjang gelombang (L). Tahap yang terakhir adalah mencari nilai PB berdasarkan perhitungan analitik dan data eksperimen. Hasil penelitian menunjukan nilai PB untuk kecepatan putar wavemaker 50 rpm dan 80 rpm adalah masing-masing sebesar 15,513% dan 8,5%. Berdasarkan nilai PB tersebut dapat dikatakan bahwa data eksperimen mendekati perhitungan analitik. Kata Kunci: Gelombang, wavemaker tipe piston, percentage model bias (PB)

scholarly journals Pengaruh Screen Layer Breakwater Terhadap Tinggi Run UP Gelombang pada Revetmen

2018 ◽  
Vol 5 (1) ◽  
pp. 7
Author(s):  
Budiman Budiman
Keyword(s):  
Wave Height ◽  
Model Simulation ◽  
Wave Length ◽  
Dimensional Parameter ◽  
Number Of Layers ◽  
Waves And Currents ◽  
Run Up ◽  
Physical Model Simulation ◽  
The Relationship ◽  
Textile Fabric

Erosion that occurs in revetment by waves and currents is a serious problem along coastal and inland shore 1. The aims of the study are to obtain influential parameter, to reduce the height of run up in the revetmet and get a non dimensional parameter of the relationship between the wave height and the wave run up on the revetment. The research is an experimental research with 2D physical model simulation, conducted in the laboratory of with some configurations of screen layer breakwater configuration models made from textile fabric with density and number of layer of different models. The model scale was 1:10 with three variations for models ((M1SL, M2SL, and M3SL) with variations of wave length and wave height, on some level of depth: 20, 15, and 10 cm. The results of the research indicated that the parameters found in this study are wave period (T), wave height (H), water depth (d), screen density (), the number of layers (N) and the distanceof the screen (Xm). The run up tend to decrease as the screen density value has smaller number of layers (N) and the distanceof the screen (Xm). In general, the study indicated that the stake of the screen layer can reduce the height of the run up in the revetment structure . The slope tan300 was 33% and produces non regression equation that shows the relationship between the dimensionless parameterwith run up (Ru/H), obtained Ru/H =, where= (); a and b respectively 2.9935 and 0.1293.

scholarly journals UJI MODEL FISIK RAYAPAN GELOMBANG PADA REVETMEN BUIS BETON

2021 ◽  
Vol 12 (1) ◽  
pp. 15-24
Author(s):  
Juventus Welly Radianta Ginting ◽  
Eduardo Meyrianso Simanjuntak ◽  
Ida Ayu Irawati Diah Ratna Putra
Keyword(s):  
Wave Height ◽  
Continuous Wave ◽  
Precast Concrete ◽  
Physical Modelling ◽  
Video Camera ◽  
Test Scenario ◽  
Incoming Wave ◽  
Wave Flume ◽  
Run Up ◽  
Structure Height

Buis Beton (Precast concrete pipe) revetment is a common coastal structure to protect the shoreline from erosion. However, it is common that this type of structure face high wave run up. A continuous wave run up on the slope of the structure may reduce the life service of Buis Beton revetment. The objective of this research is to create scientific based guidance to design an efficient Buis Beton revetment against wave run up. A physical modelling test is conducted to understand the relationship between wave run up and Buis Beton revetment. The test scenario is based on the slope of the structure (θ), structure height (L), buis beton diameter (φ), incoming wave height (Hi) and wave period (T). The physical modelling is conducted in 2D wave flume with laboratory scale of 1:10 with regular wave simulation. Wave run up is observed using a video camera which is later processed digitally to acquire the wave run up data. This research shows that the relative wave run up has a reciprocal functional relationship with the Iribarren Number parameter. In general, wave run up height on Buis Beton revetment is less than or equal to 2.64 the wave height, Hm0.Keywords: Revetment, buis beton, wave run-up, physical modelling

scholarly journals A SIMILARITY PARAMETER FOR BREAKWATERS: THE MODIFIED IRIBARREN NUMBER

2018 ◽  
pp. 28
Author(s):  
Maria Clavero ◽  
Pedro Folgueras ◽  
Pilar Diaz-Carrasco ◽  
Miguel Ortega-Sanchez ◽  
Miguel A. Losada
Keyword(s):  
Incident Wave ◽  
Wave Length ◽  
Slope Angle ◽  
Wave Pattern ◽  
Relative Width ◽  
Scattering Parameter ◽  
Wave Regime ◽  
Similarity Parameter ◽  
Mean Water Level ◽  
Run Up

In the 14th ICCE, Battjes (1974) showed that a single similarity parameter only, embodying both the effects of slope angle and incident wave steepness, was important for many aspects of waves breaking on impermeable slopes, and suggested to call it the "Iribarren number", denoted by "Ir". Ahrens and McCartney (1975) verified the usefulness of Ir to describe run-up and stability on rough permeable slopes. Since then, many researchers applied Ir to characterize and to develop formulae for the design of breakwaters and to verify their stability. On the other hand, depending on their typology, breakwaters reflect, dissipate, transmit, and radiate incident wave energy. Partial standing wave patterns are likely to occur at all types of breakwater, thus playing an important role in defining the wave regime in front of, near (seaward and leeward), and inside the breakwater. The characteristics of the porous medium, relative grain size D/L and relative width, Aeq/L2, are relevant magnitudes in that wave pattern (Vilchez et al. 2016), being D the grain diameter, L the wave length and Aeq the porous area per unit section under the mean water level. Aeq/L2 is a scattering parameter controlling the averaged transformation of the wave inside the porous section of the structure. For a vertical porous breakwater (Type A), Aeq is simply B · h, and for a constant depth, the scattering parameter is reduced to B/L, which is the relative breakwater width.

scholarly journals THE EXTENT OF AGRICULTURAL LAND DAMAGE IN VARIOUS TSUNAMI WAVE HEIGHT SCENARIOS: DISASTER MANAGEMENT AND MITIGATION

2018 ◽  
Vol XLII-3/W4 ◽  
pp. 51-57 ◽  
Author(s):  
S. Antoni ◽  
R. A. Bantan ◽  
H. M. Taki ◽  
W. Anurogo ◽  
M. Z. Lubis ◽  
...  
Keyword(s):  
Wave Height ◽  
Vegetation Index ◽  
Agricultural Land ◽  
Numerical Data ◽  
Earthquake Hazard ◽  
Case Scenario ◽  
Worst Case ◽  
Large Power ◽  
Aster Image ◽  
Run Up

<p><strong>Abstract.</strong> The southern coastal areas of Java are highly vulnerable areas of earthquake hazard because they located 200&amp;thinsp;km from the southern Java subduction zone. This zone is an active seismicity area, resulting in many tectonic earthquakes caused by collisions and shift between the plates. This shift when it occurs under the sea surface with a large power intensity can lead to a tsunami. This research conducted to identify the extent of agricultural land (AL) damaged by the tsunami for disaster risk management and mitigation. Numerical modelling was performed to determine the run-up height of the tsunami through numerical data. This model was designed using the worst-case scenario. The tsunami inundation model analysed from the coming wave (run-up) with a height of 30&amp;thinsp;m. This model used scenarios of tsunami run-up height in a coastline, coarse coefficient and slope. The data extracted using remote sensing (RS) data was the slope obtained from the ASTER image GDEM data, the agricultural land productivity data obtained using NDVI vegetation index transformation and field data on productivity, and tsunami hazard analysis with various altitude scenarios using run-up model impact on existing AL conditions. The elevation-data was obtained from the 15&amp;thinsp;m ASTER image data (GDEM) that was reclassified into a slope class map. The risk of destruction of AL based on wave height extracted by using RS data generated rice risk loss index of AL of 190.5071&amp;thinsp;tons for a height of 1&amp;thinsp;m, 1851.522&amp;thinsp;tons for a height of 5&amp;thinsp;m, 7402.71&amp;thinsp;tons for a height of 10&amp;thinsp;m, 10776.47&amp;thinsp;tons to a height of 15&amp;thinsp;m, 11823.9&amp;thinsp;tons for height 20&amp;thinsp;m, and 11824.27&amp;thinsp;tons to a height of 30&amp;thinsp;m.</p>

Study of a Wave Absorber in Various Distance Placed in a Sinusoidal Propagate Wave

2013 ◽  
Vol 302 ◽  
pp. 326-331 ◽  
Author(s):  
Zhen Zhong Yuan ◽  
Bhupendra Singh Chauhan ◽  
Hee Chang Lim
Keyword(s):  
Wind Wave ◽  
Wave Length ◽  
Ocean Waves ◽  
Floating Body ◽  
Environmental Condition ◽  
Wave Flume ◽  
Strong Source ◽  
Wave Heights ◽  
Ocean Environment ◽  
Fundamental Equations

Since there has been a rapid progress to understand the dynamics of an offshore floating body under an ocean environment, we undertake to generate the ocean waves in a lab-scale wind-wave flume. The study is aiming to observe and optimize the similar ocean environmental condition as input wave and to reduce the wall reflective wave. Several absorption methods are suggested to optimize the propagate wave by measuring the maximum and minimum of the standing wave envelope. There has been no optimized absorption method, as they highly depend on the wave period and the wave length. One of the methods - two fixed wave gauges measuring two wave heights and one wave phase - is applied in this study. In the present paper various approaches were used to analyze the results using the flume, by position of probes, with absorber and without absorber, different position, condition and angle of the wave absorber, This paper also focuses on the analysis of fundamental equations which describe the separating method of the incident and reflective wave, and finally we confirm that the wave absorber is highly efficient considering all the permutation and combination.From the study it is clear that there is a change in the wave amplitude at the receiving end then the generated end; wave absorber is a strong source to control the energy of the coming wave. With the changing the period of the wave, the reflectance is increasing when the period becomes larger.

scholarly journals Wave Interaction with Single and Twin Vertical and Sloped Slotted Walls

2020 ◽  
Vol 8 (8) ◽  
pp. 589
Author(s):  
Mohamad Alkhalidi ◽  
Noor Alanjari ◽  
S. Neelamani
Keyword(s):  
Energy Dissipation ◽  
Transmission Coefficient ◽  
Wave Height ◽  
Wave Reflection ◽  
Wave Length ◽  
Wave Interaction ◽  
Wave Transmission ◽  
Random Wave ◽  
Dissipation Coefficient ◽  
Energy Dissipation Coefficient

The interaction between waves and slotted vertical walls was experimentally studied in this research to examine the performance of the structure in terms of wave transmission, reflection, and energy dissipation. Single and twin slotted barriers of different slopes and porosities were tested under random wave conditions. A parametric analysis was performed to understand the effect of wall porosity and slope, the number of walls, and the incoming relative wave height and period on the structure performance. The main focus of the study was on wave transmission, which is the main parameter required for coastal engineering applications. The results show that reducing wall porosity from 30% to 10% decreases the wave transmission by a maximum of 35.38% and 38.86% for single and twin walls, respectively, increases the wave reflection up to 47.6%, and increases the energy dissipation by up to 23.7% on average for single walls. For twin-walls, the reduction in wall porosity decreases the wave transmission up to 26.3%, increases the wave reflection up to 40.5%, and the energy dissipation by 13.3%. The addition of a second wall is more efficient in reducing the transmission coefficient than the other wall parameters. The reflection and the energy dissipation coefficients are more affected by the wall porosity than the wall slope or the existence of a second wall. The results show that as the relative wave height increases from 0.1284 to 0.2593, the transmission coefficient decreases by 21.2%, the reflection coefficient decreases by 15.5%, and the energy dissipation coefficient increases by 18.4% on average. Both the transmission and the reflection coefficients increase as the relative wave length increases while the energy dissipation coefficient decreases. The variation in the three coefficients is more significant in deep water than in shallower water.

scholarly journals WAVE RUN-UP AT SEA DIKES UNDER OBLIQUE WAVE APPROACH

1982 ◽  
Vol 1 (18) ◽  
pp. 50
Author(s):  
E. Tautenhain ◽  
S. Kohlhase ◽  
H.W. Partenscky
Keyword(s):  
Irregular Waves ◽  
Wave Direction ◽  
Wave Runup ◽  
Natural Conditions ◽  
Wave Impact ◽  
Oblique Wave ◽  
Wave Flume ◽  
Wave Approach ◽  
Impact Forces ◽  
Run Up

Besides wave impact forces, erosion of the inner side of a sea dike is a serious cause of destruction. Therefore, wave run-up and overtopping effects have to be considered with respect to the safety of a dike. Strong relations were found between both these influences (TAUTENHAIN et.al., 1980, 1981, 1982), based on experiments in a wave flume and using an energy conservation concept. However, under natural conditions, an oblique wave approach has to be considered. This paper deals with the influence of wave direction on wave runup on a smooth dike slope in order to provide a basis for calculating the overtopping rates for both regular and irregular waves.

Laboratory Simulation and Analysis of Wave Groups

2006 ◽  
Author(s):  
R. Balaji ◽  
S. A. Sannasiraj ◽  
V. Sundar
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Region Of Interest ◽  
Offshore Structures ◽  
Laboratory Simulation ◽  
Frequency Of Occurrence ◽  
Wave Groups ◽  
Wave Flume ◽  
The Stability ◽  
Wave Elevations

The coastal and offshore structures are some times exposed to group of waves with successive higher wave elevations exceeding the significant wave height, which is considered to be vulnerable for the stability of the structures. Hence, the knowledge on the existence and frequency of occurrence of ocean wave groups at a particular region of interest is important for the design of the ocean structures. In the present study, the wave groups were simulated theoretically and the same was generated in the laboratory wave flume. The measured wave elevations were analysed through statistical, spectral and wavelet approaches to detect the existence of the groupiness.

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