scholarly journals Impact Pressure Distribution on a Monopile Structure Excited by Irregular Breaking Wave

2018 ◽  
Vol 25 (s1) ◽  
pp. 29-35 ◽  
Author(s):  
Duje Veic ◽  
Wojciech Sulisz
Keyword(s):  
Pressure Distribution ◽  
Load Distribution ◽  
Breaking Waves ◽  
Impact Pressure ◽  
Engineering Practice ◽  
Breaking Wave ◽  
Vertical Load ◽  
Shape Distribution ◽  
Significant Difference ◽  
Temporal Pressure

Abstract The problem of impact pressure distribution on a monopole structure excited by irregular breaking waves is investigated. The analysis is performed by applying a numerical model that combines potential flow model with a Navier-Stokes/VOF solution. The temporal pressure distribution is analysed for two breaking wave cases characterized by the significant difference in the steepness of the wave front. The peak impact pressures are observed in the region below the overturning wave jet where the pressure increases rapidly resulting in a peak value of the slamming coefficient equal to Cs=2π. The vertical load distribution provided by the derived model is more realistic than a rectangular shape distribution applied in engineering practice. This is because the vertical load distribution strongly depends on breaking wave shape and it is difficult to uniquely approximate such a load distribution by a rectangle.

scholarly journals Influence of the Spatial Pressure Distribution of Breaking Wave Loading on the Dynamic Response of Wolf Rock Lighthouse

2021 ◽  
Vol 9 (1) ◽  
pp. 55
Author(s):  
Darshana T. Dassanayake ◽  
Alessandro Antonini ◽  
Athanasios Pappas ◽  
Alison Raby ◽  
James Mark William Brownjohn ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Pressure Distribution ◽  
Distinct Element ◽  
Breaking Waves ◽  
Breaking Wave ◽  
Wave Loading ◽  
Wave Impact ◽  
Pressure Distributions ◽  
Impact Area ◽  
The Impact

The survivability analysis of offshore rock lighthouses requires several assumptions of the pressure distribution due to the breaking wave loading (Raby et al. (2019), Antonini et al. (2019). Due to the peculiar bathymetries and topographies of rock pinnacles, there is no dedicated formula to properly quantify the loads induced by the breaking waves on offshore rock lighthouses. Wienke’s formula (Wienke and Oumeraci (2005) was used in this study to estimate the loads, even though it was not derived for breaking waves on offshore rock lighthouses, but rather for the breaking wave loading on offshore monopiles. However, a thorough sensitivity analysis of the effects of the assumed pressure distribution has never been performed. In this paper, by means of the Wolf Rock lighthouse distinct element model, we quantified the influence of the pressure distributions on the dynamic response of the lighthouse structure. Different pressure distributions were tested, while keeping the initial wave impact area and pressure integrated force unchanged, in order to quantify the effect of different pressure distribution patterns. The pressure distributions considered in this paper showed subtle differences in the overall dynamic structure responses; however, pressure distribution #3, based on published experimental data such as Tanimoto et al. (1986) and Zhou et al. (1991) gave the largest displacements. This scenario has a triangular pressure distribution with a peak at the centroid of the impact area, which then linearly decreases to zero at the top and bottom boundaries of the impact area. The azimuthal horizontal distribution was adopted from Wienke and Oumeraci’s work (2005). The main findings of this study will be of interest not only for the assessment of rock lighthouses but also for all the cylindrical structures built on rock pinnacles or rocky coastlines (with steep foreshore slopes) and exposed to harsh breaking wave loading.

scholarly journals Impact pressure distribution of inverted arch plunge pool for large discharge

2019 ◽  
Vol 20 (1) ◽  
pp. 209-218
Author(s):  
Yu Wang ◽  
Yaan Hu ◽  
Jinde Gu ◽  
Yu Peng ◽  
Yang Xue
Keyword(s):  
Pressure Distribution ◽  
High Water ◽  
Impact Pressure ◽  
Engineering Practice ◽  
Plunge Pool ◽  
Novel Approach ◽  
Water Head ◽  
Relative Errors ◽  
The Impact ◽  
Large Discharge

Abstract In view of high water head and large discharge in the release structures of hydraulic projects, the inverted arch plunge pool has been put forward due to higher overload capability and stability. Impact pressure on the bottom is a serious concern in design safety precautions, however, the quantitative impact pressure distribution in the inverted arch plunge pool is not yet elucidated. In this study, a novel approach is presented to estimate the impact pressure of an inverted arch plunge pool. Impact pressure characteristics are experimentally investigated under different hydraulic conditions. The results detailed the effect of relative discharge coefficient and the deflection angle relative to the vertical central axis of the plunge pool bottom. The predicting formulas of impact pressure distribution are derived within small relative errors, and the proposed approaches have good applicability in three case studies. The achievements of this investigation are used to define issuance parameters relevant for engineering practice.

scholarly journals Characteristics of Breaking Wave Forces on Piles over a Permeable Seabed

2021 ◽  
Vol 9 (5) ◽  
pp. 520
Author(s):  
Zhenyu Liu ◽  
Zhen Guo ◽  
Yuzhe Dou ◽  
Fanyu Zeng
Keyword(s):  
Wave Breaking ◽  
Stokes Equations ◽  
Slope Angle ◽  
Wave Force ◽  
Breaking Waves ◽  
Offshore Wind ◽  
Secondary Wave ◽  
Wave Forces ◽  
Breaking Wave ◽  
Breaking Wave Forces

Most offshore wind turbines are installed in shallow water and exposed to breaking waves. Previous numerical studies focusing on breaking wave forces generally ignored the seabed permeability. In this paper, a numerical model based on Volume-Averaged Reynolds Averaged Navier–Stokes equations (VARANS) is employed to reveal the process of a solitary wave interacting with a rigid pile over a permeable slope. Through applying the Forchheimer saturated drag equation, effects of seabed permeability on fluid motions are simulated. The reliability of the present model is verified by comparisons between experimentally obtained data and the numerical results. Further, 190 cases are simulated and the effects of different parameters on breaking wave forces on the pile are studied systematically. Results indicate that over a permeable seabed, the maximum breaking wave forces can occur not only when waves break just before the pile, but also when a “secondary wave wall” slams against the pile, after wave breaking. With the initial wave height increasing, breaking wave forces will increase, but the growth can decrease as the slope angle and permeability increase. For inclined piles around the wave breaking point, the maximum breaking wave force usually occurs with an inclination angle of α = −22.5° or 0°.

Impact pressure distribution of an SC-CO2 jet used in rock breakage

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yong Liu ◽  
Juan Zhang ◽  
Jianping Wei ◽  
Chenchen Wang ◽  
Jiawei Cui
Keyword(s):  
Pressure Distribution ◽  
Impact Pressure ◽  
Rock Breakage

Relation Between Flow Velocity and Impact Pressure in a Green Water Flow

2013 ◽  
Author(s):  
Kusalika Ariyarathne ◽  
Kuang-An Chang ◽  
Richard Mercier
Keyword(s):  
Kinetic Energy ◽  
Void Fraction ◽  
Pressure Rise ◽  
Impact Pressure ◽  
Breaking Wave ◽  
Wave Condition ◽  
Wall Impingement ◽  
Impact Coefficient ◽  
The Impact ◽  
Mean Kinetic Energy

Impact pressure due to plunging breaking waves impinging on a simplified model structure was investigated in the laboratory based on two breaking wave conditions: the wall impingement wave condition and the deck impingement wave condition. Pressure, void fraction, and velocities were measured at various locations on the deck surface. Impact pressure was correlated with the mean kinetic energy calculated based on the measured mean velocities and void fraction to obtain the impact coefficient. For the wall impingement wave condition, the relationship between impact pressure and mean kinetic energy is linear with the impact coefficient close to unity. For the deck impingement wave condition, the above relationship does not show good correlation, whereas the impact coefficient was found to be a function of the rate of pressure rise.

scholarly journals NON-BREAKING AND BREAKING WAVE LOADS ON A COOLING WATER OUTFALL

1978 ◽  
Vol 1 (16) ◽  
pp. 148
Author(s):  
G.R. Mogridge ◽  
W.W. Jamieson
Keyword(s):  
Water Level ◽  
Cooling Water ◽  
High Water ◽  
Breaking Waves ◽  
Irregular Waves ◽  
Scale Model ◽  
Breaking Wave ◽  
Wave Loads ◽  
Eastern Canada ◽  
Spilling Breakers

Cooling water from a power generating station in Eastern Canada is pumped to an outfall and distributed into the ocean through discharge ports in the sidewalls of a diffuser cap. The cap is essentially a shell-type structure consisting of a submerged circular cylinder 26.5 ft in diameter and 14 ft high. It is located in 25 ft of water at low water level and 54 ft at high water level. Horizontal forces, vertical forces and overturning moments exerted by waves on a 1:36 scale model of the diffuser cap were measured with and without cooling water discharging from the outfall. Tests were run with regular and irregular waves producing both non-breaking and breaking wave loads on the diffuser cap. The overturning moments measured on the diffuser cap were up to 150 percent greater than those on a solid submerged cylinder sealed to the seabed. Unlike sealed cylinders, all of the wave loads measured on the relatively open structure reached maximum values at approximately the same time. The largest wave loads were measured on the diffuser structure when it was subjected to spilling breakers at low water level. For a given wave height, the spilling breakers caused wave loads up to 100 percent greater than those due to non-breaking waves.

scholarly journals Composite Single-Bolted Joint Simulation for Dynamic Strength Prediction

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 512
Author(s):  
Zeliang Yu ◽  
Pu Xue ◽  
Yue Chen
Keyword(s):  
Composite Structures ◽  
Dynamic Properties ◽  
Dynamic Strength ◽  
Structural Deformation ◽  
Engineering Practice ◽  
Three Dimension ◽  
Bolted Joint ◽  
Finite Element Software ◽  
Composite Joint ◽  
Significant Difference

Composite material has been widely used in various fields for its high specific strength and high specific stiffness, so the connectors applicable to composite structures capture many researchers’ attention. With the advantages of higher carrying capacity and repetitive assembling and disassembling, bolted joint becomes one of the most popular connectors in engineering practice. Cutting off the fiber and causing stress concentration are more serious to composite than metal, so it is necessary to predict the strength of the composite joints. Most investigations focus on the response under quasi-static loading, while dynamic effects should be in consideration in increasing impact conditions. The dynamic mechanical properties of composite joint may have a significant impact on the structural deformation and damage modes. For this purpose, this paper conducts dynamic composite single-bolted joint simulations in ABAQUS/Explicit, which used for predicting dynamic strength of the composite joint. T800/X850 laminates were tested to investigate their dynamic properties in our lab. Then the three-dimension progression damage model was established, while the dynamic constitutive model, damage initial criteria and damage evolution law of composite materials were coded in VUMAT of the finite element software ABAQUS/Explicit. The model was validated by quasi-static experiments of composite joint. The simulation results indicate that the yield strength and ultimate strength of the single-bolted composite joint are obviously increasing when consider the strain rate effect and dynamic loading. And the load-displacement curves show significant difference in damage stage. The main damages are sub-layer buckling and fiber breakage caused by extrusion.

Microwave backscatter and acoustic radiation from breaking waves

1991 ◽  
Vol 224 ◽  
pp. 601-623 ◽  
Author(s):  
M. R. Loewen ◽  
W. K. Melville
Keyword(s):  
Microwave Power ◽  
Field Experiments ◽  
Acoustic Radiation ◽  
Mechanical Energy ◽  
Breaking Waves ◽  
Acoustic Energy ◽  
Breaking Wave ◽  
Mean Square ◽  
The Mean ◽  
Microwave Backscatter

An experimental study of the microwave backscatter and acoustic radiation from breaking waves is reported. It is found that the averaged microwave and acoustic measurements correlate with the dynamics of wave breaking. Both the mean-square acoustic pressure and the backscattered microwave power correlate with the wave slope and dissipation, for waves of moderate slope (S < 0.28). The backscattered power and the mean-square pressure are also found to correlate strongly with each other. As the slope and wavelength of the breaking wave packet is increased, both the backscattered power and the mean-square pressure increase. It is found that a large portion of the backscattered microwave power precedes the onset of sound production and visible breaking. This indicates that the unsteadiness of the breaking process is important and that the geometry of the wave prior to breaking may dominate the backscattering. It is observed that the amount of acoustic energy radiated by an individual breaking wave scaled with the amount of mechanical energy dissipated during breaking. These laboratory results are compared to the field experiments of Farmer & Vagle (1988), Crowther (1989) and Jessup et al. (1990).

scholarly journals AN EVALUATION OF SUSPENDED SEDIMENT CONCENTRATION MODELS UNDER BREAKING WAVES

2018 ◽  
pp. 42
Author(s):  
Gabriel Lim ◽  
Ravindra Jayaratne ◽  
Tomoya Shibayama
Keyword(s):  
Kinetic Energy ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Critical Evaluation ◽  
Sediment Concentration ◽  
Breaking Waves ◽  
Breaking Wave ◽  
Wave Conditions ◽  
Improved Accuracy ◽  
Bed Friction

Implementing the effects of turbulent kinetic energy (TKE) is essential in producing accurate suspended sediment concentration (SSC) models, especially under breaking wave conditions. SSC is commonly attributed to two different turbulent sources under breaking wave conditions: 1) bed-friction and 2) breaking-induced turbulent vortices. Numerous studies have endeavoured to quantify the effects of TKE and incorporate them into SSC models. To name a few: Mocke & Smith (1992, henceforth MS92), Shibayama & Rattanapitikon (1993, henceforth SR93), Jayaratne & Shibayama (2007, henceforth JS07), and Yoon et al. (2015, henceforth Y15). The present study evaluates these 4 existing SSC models and validates them against recently published datasets from the ‘CROSSTEX’ (Yoon & Cox, 2010), ‘SandT-Pro’ (Ribberink et al., 2014) and ‘SINBAD’ (vdZ et al. 2015) projects. Following critical evaluation, suggestions are made to enhance existing SSC models, and these findings are then incorporated into producing two new SSC models that indicate improved accuracy.

Identification of the under-tie pad material characteristics for stress state reduction

2019 ◽  
Vol 234 (10) ◽  
pp. 1227-1237 ◽  
Author(s):  
Jacob M Branson ◽  
Marcus S Dersch ◽  
Arthur de Oliveira Lima ◽  
J Riley Edwards ◽  
Josue Cesar Bastos
Keyword(s):  
Stress State ◽  
Pressure Distribution ◽  
Load Distribution ◽  
Track Structure ◽  
State Reduction ◽  
Track Geometry ◽  
Railroad Tracks ◽  
Material Characteristics ◽  
Heavy Haul ◽  
Insight Into

The degradation of ballast particles and concrete crossties in heavy-haul railroad tracks poses problems such as inhibiting proper drainage and disturbing track geometry. under-tie pads offer a solution to reduce crosstie–ballast stresses by improving load distribution through the track structure and reducing pressures on ballast particles and the crosstie surface. Despite the emergence of under-tie pads on heavy-haul corridors, optimal characteristics for the reduction of the tie–ballast stress state have not been defined in literature. In this research, several under-tie pad products and generic materials with various thicknesses and hardnesses were studied to identify appropriate properties of under-tie pad products for pressure distribution. The findings from this research provide an insight into how material characteristics influence the pressure mitigation performance of under-tie pads. Results from this study indicate that thickness is the most crucial metric determining under-tie pad performance in reducing ballast degradation; hardness and material type also have an effect, but to a lesser degree.

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