Wave flume

About: Wave flume is a research topic. Over the lifetime, 1627 publications have been published within this topic receiving 23335 citations.

Relationship between the frequency of transverse waves and characteristics of the flow and obstacles in open channels

Abstract: When the fluid flow passes through a cluster of rigid vertical cylinders, the overlap of shear layers and vortex resulted from the separation of the streamlines around each rod leads in the surface waves. These waves are categorized in three groups of standing oscillatory, transverse waves, and linear waves. The present study focused on this phenomenon based on laboratory tests in a rectangular flume. Wooden rods 0.35 meter in height and 0.025 meter in diameter are placed in the flow path screwed on the bottom of the laboratory flume. By changing the hydraulic conditions of the flow, four types of surface waves are observed across the laboratory flume. In the condition of wave resonance, there is a direct relationship between the wavelength and the width of laboratory flume. The current study compares the frequency of the waves for the in-line and staggered arrangements of rods. Moreover by using dimensional analysis and SPSS software, two equations are proposed for determination of frequency of free surface transverse wave generated by vortex shedding in open channels.

Study of Wave Deformation Around Floating Breakwater

Abstract: Breakwater is a structure to protect waters from wave interference. The structure separates the port basin from the open sea, so that sea waves will not enter the basin. In applying for deep water conditions, floating breakwater is more efficient than conventional types, because it requires less material. Floating breakwater is suitable for soft soils where the strength of the soil is low; and is also good for the environment. The development of floating breakwater has increased significantly in the past decade. This study focuses on the magnitude of the wave transmission coefficient. Two types of floating breakwater were tested, namely FBW Type-1 and FBW Type-2, using physical modeling as well as numerical model (FLOW3D software). The experimental model was carried out in 50 m long of wave flume equipped with a regular wave generator. The study results transmission coefficient ranged from 0.53 to 0.91. Based on the results, therefore more study is needed to get better coefficient.

Numerical study on movement of tsunami boulder and storm boulder by sph method

Abstract: Smoothed Particle Hydrodynamics (SPH) is known as very useful method for large deformation problems, such as movement of wave absorbing blocks and sliding of caisson breakwater. Also, in the coastal area, boulders launched by tsunami and by high waves with typhoons (named tsunami boulders and storm boulders) are focused on because of risk assessment towards the tsunami or super typhoons. However, the difference of their movement mechanism have been rarely investigated in detail. This study aims to simulate the movement of the tsunami boulders and storm boulders, comparing with the hydraulic experiment, and evaluating the transport characteristics. Wave elevation and boulder displacement were reproduced in the numerical wave flume well compared to physical model. Also, there is difference between solitary and irregular waves when waves act on boulders.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/WOfXbU7m_8E

Measuring impact loads on rigid coastal structures

Abstract: The aim of this work is the study of laboratory effects on the measurement of wave impact induced loads on rigid maritime structures. A high number of experiments (more then 4000 using regular wave attacks) have been carried out in the small scale wave flume "CIEMito" in the laboratory of the LIM-UPC BarcelonaTech. The effects on the results of sample frequency, measurement systems and experimental layout has been deeply studied. A high number of repetitions of the same wave attack has been performed in order to have statistically robust results since the almost-random behavior of the studied phenomenon. -Sample frequencies from 50 to 19200 Hz - Load cells, pressure transducers and an innovative tactile pressure map - Six different experimental layouts effects have been tested The maximum results of force and pressures have been always measured at the maximum sample frequency. Differences of the 150% has been found between the measurements at 50 and 19200 Hz. The total load measured considering all the width of the flume tends to sub estimate the total force measured only in a slice in the middle of the flume. Even if the average value is comparable, the pressure transducers tends to return much spread results than the load cells. The tactile pressure mapping system stands out for his very high spatial density (196 sensels in a 49cm2 area) but an experimental specific calibration and an ad-hoc set-up are necessary for the utilization with water and in order to can collect reliable results comparable with the classic measurement systems. For this work 3 types of calibration methodology have been compared: static, instrumented pendulum and water jets. The last has to be considered the best choice and the selected for the definitive tests. Among all the results the ones to be highlighted are: the integral of pressures (the force applied over the whole sensor) acting on the tactile sensor differ from simultaneous load cell measurements by less than ±20%. The pressure mapping system tends to underestimate the pressure peak. However, if the average values of the 3, 5 and 10 highest peaks are considered they differ by up to ±10%. Has been shown a reduction effect of the pressure peak when pressure measurement systems are coupled with load cells. A perfect set-up for these kind of measurement hasn't found yet but the combination of the three measurement systems seems to be the best possible solution. Load cells return a direct and reliable result of the total load, but the set-up could be complicated especially at large scales. The pressure mapping system neither seems to be the perfect alternative to the pressure transducers and a combined use is suggested for these experiments that require a high level of precision both in space and magnitude. A sample frequency around 4000 Hz, for small scale experiments, present the right combination between sample density, memory storage and added signal noise for the correct characterization of the impulsive phenomenon of the wave generated violent impact loads on rigid structures. Considering a working scale in between 1/50 and 1/100, a frequency of 500Hz is proposed for measurement at full scale. Following these methodologic recommendations not only will permit better and more reliable measurement but also will permit a better comprehension/evaluation of the test and analysis uncertainties. In this manner it will be possible to extrapolate, in a reliable way, scale test results to the design process of breakwaters.