scholarly journals Validation of pressure-impulse theory for standing wave impact loading on vertical hydraulic structures with short overhangs

2020 ◽  
Vol 159 ◽  
pp. 103702 ◽  
Author(s):  
Ermano de Almeida ◽  
Bas Hofland
Keyword(s):  
Standing Wave ◽  
Impact Loading ◽  
Hydraulic Structures ◽  
Wave Impact ◽  
Pressure Impulse

Wave Impact on a Wall Using Pressure-Impulse Theory. I: Trapped Air

2000 ◽  
Vol 126 (4) ◽  
pp. 182-190 ◽  
Author(s):  
Deborah J. Wood ◽  
D. Howell Peregrine ◽  
Tom Bruce
Keyword(s):  
Wave Impact ◽  
Pressure Impulse ◽  
Trapped Air

Methods of detectiоn a voids under concrete slabs of water faces of the dam of Novosibirsk hydrostation by the standing wave method

2020 ◽  
Author(s):  
Konstantin V. Fedin ◽  
◽  
Yury I. Kolesnikov ◽  
Luckymore Ngomayezwe ◽  
◽  
...  
Keyword(s):  
Standing Wave ◽  
Acoustic Noise ◽  
Standing Waves ◽  
Hydraulic Structures ◽  
Concrete Slabs ◽  
Wave Method ◽  
Compression Waves ◽  
Standing Wave Method ◽  
Amplitude Spectra ◽  
Base Soil

Using the example of the Novosibirsk hydrostation, the capabilities of the standing wave method to identify defects in the fastenings of water faces of dams of hydraulic structures are demonstrated. The accumulation of amplitude spectra of acoustic noise records allows one to determine the frequencies of the few first modes of standing compression waves generated by noise in concrete slabs. A sharp increase in the frequency of the lowest mode of standing waves is an indicator of the appearance of voids under the slabs or decompression of the base soil.

CFD Modeling of a Submersible in a Realistic Surfaced Sea State Condition for Predictions of Hydrodynamic Wave Impact Loading

2011 ◽  
Author(s):  
Minyee Jiang ◽  
David Drazen ◽  
Jack R. Lee
Keyword(s):  
Impact Loading ◽  
Impact Load ◽  
Fluid Dynamic ◽  
Scale Model ◽  
Cfd Modeling ◽  
Contributing Factors ◽  
Wave Impact ◽  
Water Line ◽  
Wave Slamming ◽  
Hydrodynamic Wave

Topside features on submersibles are subject to wave impact loading while surfaced. At the surface, operations are typically conducted at low to zero ship speeds so hydrodynamic loading is dominated by wave loading as opposed to bow/wave slamming which is typically evaluated for surface ships. The typical circular or cylindrical hull situated mainly below the water line places topside features right around the mean water line, where the largest wave impact loading is expected. The roll, heave, and pitching motion of such a hull shape and the curvature of the hull at the water surface may result in a different distribution of wave impact loading when compared to the expected loading on typical surface ship hull. Current studies have been conducted using traditional scale-model experiments complimented with computational fluid dynamic (CFD) methods to improve the predictions and the understanding of the contributing factors to the wave impact loading. The end goal is to try to validate CFD modeling methods for these submersible design cases to support the design process. The end products are design wave impact load requirements and ship operating guidance to help avoid damage due to wave impact load conditions.

Full-Scale Measurements of Wave Impact Loading on a Flat Plate

2012 ◽  
Author(s):  
David Drazen ◽  
Eric Terrill ◽  
Don Walker ◽  
Joel Hazard ◽  
Tom Cook ◽  
...  
Keyword(s):  
Flat Plate ◽  
Impact Loading ◽  
Extended Period ◽  
Full Scale ◽  
Wave Forces ◽  
Flat Plates ◽  
Wave Impact ◽  
Incoming Wave ◽  
Engineering Design Problems ◽  
Wide Range

Full scale measurements of wave impact loads and their statistics in real sea states are desirable for validation of numerical simulations and for application to marine engineering design problems. Measuring and/or estimating wave forces on flat plates are especially problematic due to statistics of large waves in a given sea state, the intermittent statistics of wave breaking, the sensitivity of the loading relative to the phase of the incoming wave and scaling issues when translating from model scale data to full-scale. To increase our understanding of wave hydrodynamic pressures on a flat plate, an instrumented plate was deployed from the Scripps Institution of Oceanography’s research pier. The instrumented plate is exposed to a wide range of wave conditions with Hs ranging from 3–4 m in the winter and with Hs in the 1–2 m range in the summer. The instrumented flat plate is composed of three discrete modules containing 6 pressure gages. Data are being collected over a extended period, nominally 12 months, to characterize extreme value distributions due to wave impact loading.

scholarly journals Violent Wave Impact on Vertical Wall using Pressure-Impulse Theory

2007 ◽  
Vol 54 ◽  
pp. 811-815
Author(s):  
Nguyen Danh Thao ◽  
Hiroshi TAKAGI ◽  
Tomoya SHIBAYAMA
Keyword(s):  
Vertical Wall ◽  
Wave Impact ◽  
Pressure Impulse

Vertical Wave Impact Loading on a Fixed Platform Deck

2015 ◽  
Author(s):  
Jule Scharnke ◽  
Janou Hennig
Keyword(s):  
Impact Loading ◽  
Maximum Load ◽  
Primary Objective ◽  
Model Tests ◽  
Test Results ◽  
Wave Impact ◽  
Sea State ◽  
Peak Period ◽  
Significant Difference ◽  
Crest Length

The TLP model tests in CresT [1] showed that there is a significant difference in the maximum load events due to long-crested and short-crested waves of same peak period and significant wave height. This decrease in load amplitudes for increasing spreading was not dominated by the reduction in crest heights, but related to a change in wave excitation. In ShorT-CresT wave-in-deck model tests were carried out with the focus on the physics of impact loading. The primary objective of the platform tests was to link crest height and wave impact with local and global loading on the deck. The model test results showed that the global vertical loads in short-crested waves can be similar to long-crested events, if the wetted deck area is comparable. In other words, the platform deck loading corresponds to the relative short-crestedness of the sea state: if the crest length is at least as large as the characteristic deck dimension, the loads are significantly larger than for lower crest lengths (step change). In this paper the results of the wave-in-deck model tests are presented and discussed. The analysis of the model tests is focused on a comparison between short-crested and long-crested impacts and a comparison of the measurements to a simplified loading model.

scholarly journals Pressure impulse theory for a slamming wave on a vertical circular cylinder

2019 ◽  
Vol 867 ◽  
Author(s):  
Amin Ghadirian ◽  
Henrik Bredmose
Keyword(s):  
Three Dimensional ◽  
Response Prediction ◽  
Impact Angle ◽  
Circular Cylinders ◽  
Model Parameters ◽  
Short Time Scale ◽  
Wave Impact ◽  
Pressure Impulse ◽  
Maximum Angle ◽  
Crest Length

A pressure impulse model is presented for wave impact on vertical circular cylinders. Pressure impulse is the time integral of the pressure during an impact of short time scale. The model is derived for a simplistic geometry and has relative impact height, crest length and cylinder radius as effective variables. The last parameter, the maximum angle of impact, is free and can be calibrated to yield the right force impulse. A progression of simpler pressure impulse models are derived in terms of a three-dimensional box generalization of the two-dimensional wall model and an axisymmetric model for vertical cylinders. The dependence on the model parameters is investigated in the simpler models and linked to the behaviour of the three-dimensional cylinder model. The model is next validated against numerical results for a wave impact for a phase- and direction-focused wave group. The maximum impact angle is determined by calibration against the force impulse. A good match of the pressure impulse fields is found. Further comparison to the force impulse of two common models in marine engineering reveals improved consistency for the present model. The model is found to provide a promising representation of the pressure impulse field, based on a limited number of input parameters. Its further validation and potential as a robust tool in force and response prediction is discussed.

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