scholarly journals Large-scale laboratory study of breaking wave hydrodynamics over a fixed bar

2017 ◽  
Vol 122 (4) ◽  
pp. 3287-3310 ◽  
Author(s):  
Dominic A. van der A ◽  
Joep van der Zanden ◽  
Tom O'Donoghue ◽  
David Hurther ◽  
Iván Cáceres ◽  
...  
Keyword(s):  
Laboratory Study ◽  
Large Scale ◽  
Breaking Wave

scholarly journals Assessment of Numerical Methods for Plunging Breaking Wave Predictions

2021 ◽  
Vol 9 (3) ◽  
pp. 264
Author(s):  
Shanti Bhushan ◽  
Oumnia El Fajri ◽  
Graham Hubbard ◽  
Bradley Chambers ◽  
Christopher Kees
Keyword(s):  
Solitary Wave ◽  
Wave Breaking ◽  
Large Scale ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Wave Crest ◽  
Breaking Wave ◽  
Rans Turbulence Models ◽  
Run Up ◽  
Better Than

This study evaluates the capability of Navier–Stokes solvers in predicting forward and backward plunging breaking, including assessment of the effect of grid resolution, turbulence model, and VoF, CLSVoF interface models on predictions. For this purpose, 2D simulations are performed for four test cases: dam break, solitary wave run up on a slope, flow over a submerged bump, and solitary wave over a submerged rectangular obstacle. Plunging wave breaking involves high wave crest, plunger formation, and splash up, followed by second plunger, and chaotic water motions. Coarser grids reasonably predict the wave breaking features, but finer grids are required for accurate prediction of the splash up events. However, instabilities are triggered at the air–water interface (primarily for the air flow) on very fine grids, which induces surface peel-off or kinks and roll-up of the plunger tips. Reynolds averaged Navier–Stokes (RANS) turbulence models result in high eddy-viscosity in the air–water region which decays the fluid momentum and adversely affects the predictions. Both VoF and CLSVoF methods predict the large-scale plunging breaking characteristics well; however, they vary in the prediction of the finer details. The CLSVoF solver predicts the splash-up event and secondary plunger better than the VoF solver; however, the latter predicts the plunger shape better than the former for the solitary wave run-up on a slope case.

scholarly journals Do more attractive women show stronger preferences for male facial masculinity?

2019 ◽  
Author(s):  
Ciaran Docherty ◽  
Anthony J Lee ◽  
Amanda Hahn ◽  
Lisa Marie DeBruine ◽  
Benedict C Jones
Keyword(s):  
Laboratory Study ◽  
Physical Condition ◽  
Large Scale ◽  
Facial Attractiveness ◽  
Third Party ◽  
Online Study ◽  
Facial Masculinity ◽  
Per Se ◽  
Women’S Preferences

Researchers have suggested that more attractive women will show stronger preferences for masculine men because such women are better placed to offset the potential costs of choosing a masculine mate. However, evidence for correlations between measures of women’s own attractiveness and preferences for masculine men is mixed. Moreover, the samples used to test this hypothesis are typically relatively small. Consequently, we conducted two large-scale studies that investigated possible associations between women’s preferences for facial masculinity and their own attractiveness as assessed from third-party ratings of their facial attractiveness (Study 1, N = 454, laboratory study) and self-rated attractiveness (Study 2, N = 8972, online study). Own attractiveness was positively correlated with preferences for masculine men in Study 2 (self-rated attractiveness), but not Study 1 (third-party ratings of facial attractiveness). This pattern of results is consistent with the proposal that women’s beliefs about their own attractiveness, rather than their physical condition per se, underpins attractiveness-contingent masculinity preferences.

scholarly journals Can we trust untargeted metabolomics? Results of the metabo-ring initiative, a large-scale, multi-instrument inter-laboratory study

Metabolomics ◽  
2014 ◽  
Vol 11 (4) ◽  
pp. 807-821 ◽  
Author(s):  
Jean-Charles Martin ◽  
Matthieu Maillot ◽  
Gérard Mazerolles ◽  
Alexandre Verdu ◽  
Bernard Lyan ◽  
...  
Keyword(s):  
Laboratory Study ◽  
Large Scale ◽  
Untargeted Metabolomics

scholarly journals NUMERICAL MODELING OF TSUNAMI-INDUCED HYDRODYNAMIC FORCES ON ONSHORE STRUCTURES USING SPH

2012 ◽  
Vol 1 (33) ◽  
pp. 81 ◽  
Author(s):  
Philippe St-Germain ◽  
Ioan Nistor ◽  
Ronald Townsend
Keyword(s):  
Water Surface ◽  
Large Scale ◽  
Pressure Field ◽  
Hydrodynamic Forces ◽  
Small Scale ◽  
Breaking Wave ◽  
Total Force ◽  
Riemann Solver ◽  
Wave Impact ◽  
Time Histories

In this paper, the simulation of the violent impact of tsunami-like bores with a square column is performed using a single-phase, weakly compressible three-dimensional Smoothed Particle Hydrodynamics (SPH) model. In order to avoid large fluctuations in the pressure field and to obtain accurate simulations of the hydrodynamic forces, a Riemann solver-based formulation of the SPH method is utilized. Large-scale physical experiments conducted by the authors are reproduced using the numerical model. Time-histories of the water surface elevation as well as time-histories of the pressure distribution and net total force acting on the column are successfully compared. As observed in previous breaking wave impact studies, results show that the magnitude and duration of the impulsive force at initial bore impact depend on the degree of entrapped air in the bore-front. Although ensuring a stable pressure field, the Riemann solver-based SPH scheme is believed to induce excessive numerical diffusion, as sudden and large water surface deformations, such as splashing at initial bore impact, are marginally reproduced. To investigate this particular issue, the small-scale physical experiment of Kleefsman et al. (2005) is also considered and modeled.

scholarly journals DISTRIBUTION OF IMPACT INDUCED PRESSURES AT THE FACE OF UNIFORMLY SLOPED SEA DIKES: PRELIMINARY 2D EXPERIMENTAL RESULTS

2012 ◽  
Vol 1 (33) ◽  
pp. 74 ◽  
Author(s):  
Dimitris Stagonas ◽  
Gerald Muller ◽  
Karunya Ramachandran ◽  
Stefan Schimmels ◽  
Alec Dane
Keyword(s):  
Large Scale ◽  
Tactile Sensor ◽  
Breaking Waves ◽  
Horizontal Distribution ◽  
Breaking Wave ◽  
The Face ◽  
The University ◽  
The Impact ◽  
Sea Dikes ◽  
Sea Dike

Although existing knowledge on the vertical distribution of impact pressures on sea-dikes is well established only very little is known with respect to their horizontal distribution. A collaboration developed between the University of Southampton, Uk and FZK, Hannover looks in more detail at the distribution of pressures induced by waves breaking on the face of a sea-dike. For this, 2D large scale experiments with waves breaking on a 1:3 sea dike were conducted but instead of pressure transducers a tactile pressure sensor was used to map the impact pressures. Such sensors were initially used with breaking waves in the University of Southampton and their use for large scale experiments was attempted here for the first time. In the current paper the calibration and application of the tactile sensor for experiments involving up to 1m high and 8sec long waves are initially described. Preliminary results illustrating the simultaneous distribution of impact induced pressures over an area of 426.7x487.7mm are then presented. Based on these pressure maps the vertical and horizontal location of maximum breaking wave induced pressures is also deduced.

scholarly journals Biochar as a Stimulator for Germination Capacity in Seeds of Virginia Mallow (Sida hermaphrodita (L.) Rusby)

2019 ◽  
Vol 9 (16) ◽  
pp. 3213 ◽  
Author(s):  
Bogdan Saletnik ◽  
Marcin Bajcar ◽  
Grzegorz Zaguła ◽  
Aneta Saletnik ◽  
Maria Tarapatskyy ◽  
...  
Keyword(s):  
Laboratory Study ◽  
Plant Material ◽  
Large Scale ◽  
Low Cost ◽  
Control Sample ◽  
Control Group ◽  
Scale Production ◽  
Germination Capacity ◽  
Beneficial Effects ◽  
Large Scale Production

This article presents the findings of a laboratory study investigating the stimulation and conditioning of seeds with biochar and the effects observed in the germination and emergence of Virginia mallow (Sida hermaphrodita (L.) Rusby) seedlings. The study shows that biochar, applied as a conditioner added to water in the process of seed hydration, improves their germination capacity. When the processed plant material was added to water at a rate of 5 g (approx. 1250 seeds) per 100 mL, the rate of germination increased to 45.3%, and was 23.3% higher when compared to the control group, and 7.3% higher than in the seeds hydrated without biochar. The beneficial effects of biochar application were also reflected in the increased mass of Virginia mallow seedlings. The mass of seedlings increased by 73.5% compared to the control sample and by 25.9% compared to the seeds hydrated without biochar. Given the low cost of charcoal applied during the hydro-conditioning process, the material can be recommended as a conditioner in large-scale production of Virginia mallow.

Evolution of the turbulence structure in the surf and swash zones

2010 ◽  
Vol 644 ◽  
pp. 193-216 ◽  
Author(s):  
IN MEI SOU ◽  
EDWIN A. COWEN ◽  
PHILIP L.-F. LIU
Keyword(s):  
Large Scale ◽  
Surf Zone ◽  
Early Stage ◽  
Vertical Plane ◽  
Turbulence Energy ◽  
Breaking Wave ◽  
Turbulence Structure ◽  
Grid Turbulence ◽  
Mean Flow ◽  
Scale Turbulence

The velocity field and turbulence structure within the surf and swash zones forced by a laboratory-generated plunging breaking wave were investigated using a particle image velocimetry measurement technique. Two-dimensional velocity fields in the vertical plane from 200 consecutive monochromatic waves were measured at four cross-shore locations, shoreward of the breaker line. The phase-averaged mean flow fields indicate that a shear layer occurs when the uprush of the bore front interacts with the downwash flow. The turbulence characteristics were examined via spectral analysis. The larger-scale turbulence structure is closely associated with the breaking-wave- and the bore-generated turbulence in the surf zone; then, the large-scale turbulence energy cascades to smaller scales, as the turbulent kinetic energy (TKE) evolves from the outer surf zone to the swash zone. Smaller-scale energy injection during the latter stage of the downwash phase is associated with the bed-generated turbulence, yielding a −1 slope in the upper inertial range in the spatial spectra. Depth-integrated TKE budget components indicate that a local TKE equilibrium exists during the bore-front phases and the latter stage of the downwash phases in the outer surf zone. The TKE decay resembles the decay of grid turbulence during the latter stage of the uprush and the early stage of the downwash, as the production rate is small because of the absence of strong mean shear during this stage of the wave cycle as well as the relatively short time available for the growth of the bed boundary layer.

Evolution of a quasi-steady breaking wave

1995 ◽  
Vol 302 ◽  
pp. 29-44 ◽  
Author(s):  
J. C. Lin ◽  
D. Rockwell
Keyword(s):  
Free Surface ◽  
Froude Number ◽  
Large Scale ◽  
Mixing Layer ◽  
Stationary Wave ◽  
Wave Pattern ◽  
Small Scale ◽  
Radius Of Curvature ◽  
Breaking Wave ◽  
Large Radius

The stages of evolution of a quast-steady breaker from the onest of a capillary pattern to a fully evolved breaking wave are cgaracterized using high-image-density particle image velocimetry, which provides instrantaneous representations of the free surface and the patterns of vorticity beneath it. The initial stage, which sets in at a low value of Froude number, involves a capillary pattern along each trough-crest surface of a quasi-stationary wave. The successive crests of the capillary pattern exhihit increasing scale and culminate in a single largest-scale crest of the free surface. Immediately upstream of the large-scale crest, the capillary pattern shows counterclockwise concentrations of vorticity at its troughs and regions of clockwise vorticity beneath its crests. The onset of the final, largest-scale crest exhihits two forms: one involving no flow sparation; and the other exhibiting a small-scale separaed mixing layer. At an intermediate value of Froude number, a breaker occurs and the acpillary pattern is replaced by large-scale distortions of the free surface. The onset of separation, which involves flow deceleration along a region of the free surface having a large radius of curvature, leads to formation of a long mixing layeer, which has substantial levels of vorticity. Downstream of this breaker, the long-wavelength wave pattern is suppressed. At the largest value of Froude number, the onset of flow sparation rapidly occurs in conjunction with an abrupt change in slope of the surface, giving rise to vorticity concentrationa in the mixing layer.

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