scholarly journals MULTI-SCALE INFRA-GRAVITY WAVE DYNAMICS - THE FRENCH BASQUE COAST

2020 ◽  
pp. 46
Author(s):  
Volker Roeber ◽  
J. Dylan Nestler ◽  
Jonas Pinault ◽  
Assaf Azouri ◽  
Florian Bellafont
Keyword(s):  
Water Level ◽  
Gravity Wave ◽  
Numerical Study ◽  
Numerical Models ◽  
Wave Direction ◽  
Wave Dynamics ◽  
Multi Scale ◽  
Offshore Wave ◽  
A Site ◽  
Basque Coast

Phase-resolving numerical models are a powerful tool to identify and analyze dominant wave processes along a site of interest. We have carried out a numerical study related to infra-gravity wave dynamics along the French Basque coast. The computed scenarios are representative for the swell conditions at the site of interest and include variations in offshore wave height, direction, and water level. Several statistical methods were employed that illustrate that the irregular bathymetry is a key component for the strong variations in sea-swell and IG-wave energy. The water level is demonstrated to substantially affect the IG-wave behavior, more than the wave direction. Swash oscillations in the IG-frequency band are greater than or equal to sea-swell swash oscillations at nearly all locations along the studied shoreline.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/ELZwJCokkX0

scholarly journals Evolution of Meniscal Biomechanical Properties with Growth: An Experimental and Numerical Study

2021 ◽  
Vol 8 (5) ◽  
pp. 70
Author(s):  
Marco Ferroni ◽  
Beatrice Belgio ◽  
Giuseppe M. Peretti ◽  
Alessia Di Giancamillo ◽  
Federica Boschetti
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Developmental Stage ◽  
Mechanical Response ◽  
Numerical Study ◽  
Numerical Models ◽  
Mechanical Stimulus ◽  
Specific Response ◽  
Mechanical Parameters ◽  
Biochemical Analyses

The menisci of the knee are complex fibro-cartilaginous tissues that play important roles in load bearing, shock absorption, joint lubrication, and stabilization. The objective of this study was to evaluate the interaction between the different meniscal tissue components (i.e., the solid matrix constituents and the fluid phase) and the mechanical response according to the developmental stage of the tissue. Menisci derived from partially and fully developed pigs were analyzed. We carried out biochemical analyses to quantify glycosaminoglycan (GAG) and DNA content according to the developmental stage. These values were related to tissue mechanical properties that were measured in vitro by performing compression and tension tests on meniscal specimens. Both compression and tension protocols consisted of multi-ramp stress–relaxation tests comprised of increasing strains followed by stress–relaxation to equilibrium. To better understand the mechanical response to different directions of mechanical stimulus and to relate it to the tissue structural composition and development, we performed numerical simulations that implemented different constitutive models (poro-elasticity, viscoelasticity, transversal isotropy, or combinations of the above) using the commercial software COMSOL Multiphysics. The numerical models also allowed us to determine several mechanical parameters that cannot be directly measured by experimental tests. The results of our investigation showed that the meniscus is a non-linear, anisotropic, non-homogeneous material: mechanical parameters increase with strain, depend on the direction of load, and vary among regions (anterior, central, and posterior). Preliminary numerical results showed the predominant role of the different tissue components depending on the mechanical stimulus. The outcomes of biochemical analyses related to mechanical properties confirmed the findings of the numerical models, suggesting a specific response of meniscal cells to the regional mechanical stimuli in the knee joint. During maturation, the increase in compressive moduli could be explained by cell differentiation from fibroblasts to metabolically active chondrocytes, as indicated by the found increase in GAG/DNA ratio. The changes of tensile mechanical response during development could be related to collagen II accumulation during growth. This study provides new information on the changes of tissue structural components during maturation and the relationship between tissue composition and mechanical response.

Numerical Study of Corrugated Metal Panels Subjected to Windborne Debris Impacts

2014 ◽  
Vol 626 ◽  
pp. 109-114
Author(s):  
Wen Su Chen ◽  
Hong Hao ◽  
Hao Du
Keyword(s):  
Extreme Event ◽  
Numerical Study ◽  
Numerical Models ◽  
Economic Loss ◽  
Wind Loading ◽  
Windborne Debris ◽  
Study Laboratory ◽  
The Impact ◽  
Metal Panels ◽  
Corrugated Metal

Hurricane, typhoon and cyclone take place more and more often around the world with changing climate. Such nature disasters cause tremendous economic loss and casualty. Various kinds of windborne debris such as compact-like, plate-like and rod-like objects driven by hurricane usually imposes localized impact loading on the structure envelopes such as cladding, wall or roof, etc. The dominant opening in the envelope might cause serious damage to the structures, even collapse. To withstand the impact of such extreme event, the requirements on panel capacity to resist windborne debris impact has been presented in the Australian Wind Loading Code (2011) [1]. Corrugated metal panels are widely used as building envelop. In a previous study, laboratory tests have been carried out to investigate the performance of corrugated metal panels subjected to a 4kg wooden projectile by considering various impact locations, impact velocities and boundary conditions. In this study, numerical models were developed to simulate the responses of the corrugated metal panels subjected to wooden debris impacts by using commercial software LS-DYNA. The predicted data from the numerical simulations were compared with the experimental results. The validated numerical model can be used to conduct intensive numerical simulation to study the failure probabilities of corrugated structural panels subjected to windborne debris impacts.

PRELIMINARY STUDY ON NOVEL BEAM-TO-COLUMN CONNECTION BASED ON SMA PLATE

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Michael CH Yam ◽  
Ke Ke ◽  
Ping Zhang ◽  
Qingyang Zhao
Keyword(s):  
Friction Coefficient ◽  
Energy Dissipation ◽  
Numerical Study ◽  
Numerical Models ◽  
Numerical Technique ◽  
The Self ◽  
Hysteretic Behavior ◽  
The Novel ◽  
Energy Dissipation Capacity ◽  
Preliminary Study

A novel beam-to-column connection equipped with shape memory alloy (SMA) plates has been proposed to realize resilient performance under low-to-medium seismic actions. In this conference paper, the detailed 3D numerical technique calibrated by the previous paper is adopted to examine the hysteretic behavior of the novel connection. A parametric study covering a reasonable range of parameters including the thickness of the SMA plate, friction coefficient between SMA plate and beam flange and pre-load of the bolt was carried out and the influence of the parameters was characterized. In addition, the effect of the SMA Belleville washer on the connection performance was also studied. The results of the numerical study showed that the initial connection stiffness and the energy-dissipation capacity of the novel connection can be enhanced with the increase of the thickness of the SMA plate. In addition, the initial connection stiffness and energy-dissipation behavior of the novel connection can be improved by increasing the friction coefficient or pre-load of bolts, whereas the increased friction level could compromise the self-centering behavior of the connection. The hysteretic curves of the numerical models of the connection also implied that the SMA washers may contribute to optimizing the connection behavior by increasing the connection stiffness and energy-dissipation capacity without sacrificing the self-centering behavior.

An experimental and numerical study of the resonant flow between a hull and a wall

2021 ◽  
Vol 930 ◽  
Author(s):  
I.A. Milne ◽  
O. Kimmoun ◽  
J.M.R. Graham ◽  
B. Molin
Keyword(s):  
Vortex Shedding ◽  
Particle Image ◽  
Numerical Study ◽  
Numerical Models ◽  
Vertical Wall ◽  
Liquefied Natural Gas ◽  
Narrow Gap ◽  
Image Velocimetry ◽  
High Degree ◽  
Wave Induced

The wave-induced resonant flow in a narrow gap between a stationary hull and a vertical wall is studied experimentally and numerically. Vortex shedding from the sharp bilge edge of the hull gives rise to a quadratically damped free surface response in the gap, where the damping coefficient is approximately independent of wave steepness and frequency. Particle image velocimetry and direct numerical simulations were used to characterise the shedding dynamics and explore the influence of discretisation in the measurements and computations. Secondary separation was identified as a particular feature which occurred at the hull bilge in these gap flows. This can result in the generation of a system with multiple vortical regions and asymmetries between the inflow and outflow. The shedding dynamics was found to exhibit a high degree of invariance to the amplitude in the gap and the spanwise position of the barge. The new measurements and the evaluation of numerical models of varying fidelity can assist in informing offshore operations such as the side by side offloading from floating liquefied natural gas facilities.

scholarly journals Water level oscillations in Monterey Bay and Harbor

Ocean Science ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 439-453 ◽  
Author(s):  
J. Park ◽  
W. V. Sweet ◽  
R. Heitsenrether
Keyword(s):  
Water Level ◽  
Wave Energy ◽  
Normal Modes ◽  
Low Frequency ◽  
Water Levels ◽  
Level Data ◽  
Modal Amplitude ◽  
Primary Driver ◽  
Potential Mode ◽  
Offshore Wave

Abstract. Seiches are normal modes of water bodies responding to geophysical forcings with potential to significantly impact ecology and maritime operations. Analysis of high-frequency (1 Hz) water level data in Monterey, California, identifies harbor modes between 10 and 120 s that are attributed to specific geographic features. It is found that modal amplitude modulation arises from cross-modal interaction and that offshore wave energy is a primary driver of these modes. Synchronous coupling between modes is observed to significantly impact dynamic water levels. At lower frequencies with periods between 15 and 60 min, modes are independent of offshore wave energy, yet are continuously present. This is unexpected since seiches normally dissipate after cessation of the driving force, indicating an unknown forcing. Spectral and kinematic estimates of these low-frequency oscillations support the idea that a persistent anticyclonic mesoscale gyre adjacent to the bay is a potential mode driver, while discounting other sources.

scholarly journals Multi-scale structural analysis of the A-site and oxygen deficient perovskite Sr11Mo4O23

2017 ◽  
Vol 46 (37) ◽  
pp. 12466-12473 ◽  
Author(s):  
Graham King ◽  
Maxim Avdeev ◽  
Ilyas Qasim ◽  
Qingi Zhou ◽  
Brendan J. Kennedy
Keyword(s):  
Crystal Structure ◽  
Structural Analysis ◽  
Multi Scale ◽  
Local Correlations ◽  
A Site

The crystal structure of Sr11Mo4O23 and the local correlations between the disordered sites are examined.

scholarly journals Research on Water Environment Regulation of Artificial Playground Lake Interconnected Yangtze River

2018 ◽  
Vol 15 (10) ◽  
pp. 2110 ◽  
Author(s):  
Weiwei Song ◽  
Xingqian Fu ◽  
Yong Pang ◽  
Dahao Song ◽  
Qing Xu ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Level ◽  
Yangtze River ◽  
Flood Control ◽  
Numerical Models ◽  
Rapid Development ◽  
Control Level ◽  
Water Environment ◽  
Water Diversion ◽  
Coupled Models

With the rapid development of China, water pollution is still a serious problem despite implementation of control measures. Reasonable water environment management measures are very important for improving water quality and controlling eutrophication. In this study, the coupled models of hydrodynamics, water quality, and eutrophication were used to predict artificial Playground Lake water quality in the Zhenjiang, China. Recommended “unilateral” and “bilateral” river numerical models were constructed to simulate the water quality in the Playground Lake without or with water diversion by pump, sluice and push pump. Under “unilateral” and “bilateral” river layouts, total nitrogen and total phosphorus meet the landscape water requirement through water diversion. Tourist season in spring and summer and its suitable temperature result in heavier eutrophication, while winter is lighter. Under pumping condition, water quality and eutrophication of “unilateral” river is better than “bilateral” rivers. Under sluice diversion, the central landscape lake of “unilateral river” is not smooth, and water quality and eutrophication is inferior to the “bilateral”. When the water level exceeds the flood control level (4.1 m), priority 1 is launched to discharge water from the Playground Lake. During operation of playground, when water level is less than the minimum level (3.3 m), priority 2 is turned on for pumping diversion or sluice diversion to Playground Lake. After opening the Yangtze river diversion channel sluice, priority 3 is launched for sluice diversion to the Playground Lake. When the temperature is less than 15 °C, from 15 °C to 25 °C and higher than 25 °C, the water quality can be maintained for 15 days, 10 days and 7 days, respectively. Corresponding to the conditions of different priority levels, reasonable choices of scheduling measures under different conditions to improve the water quality and control eutrophication of the Playground Lake. This article is relevant for the environmental management of the artificial Playground Lake, and similar lakes elsewhere.

A Two-Region Model for Gradient Modification of Salt-Gradient Solar Ponds by Radial Injection

1996 ◽  
Vol 118 (1) ◽  
pp. 37-44 ◽  
Author(s):  
G. A. Eghneim ◽  
S. J. Kleis
Keyword(s):  
Turbulence Model ◽  
Field Model ◽  
Numerical Study ◽  
Numerical Models ◽  
Domain Boundary ◽  
Near Field ◽  
Solar Ponds ◽  
Numerical Predictions ◽  
Region Model ◽  
Salt Gradient

A combined experimental and numerical study was conducted to support the development of a new gradient maintenance technique for salt-gradient solar ponds. Two numerical models were developed and verified by laboratory experiments. The first is an axisymmetric (near-field) model which determines mixing and entrainment in the near-field of the injecting diffuser by solving the conservation equations of mass, momentum, energy, and salt. The model assumes variable properties and uses a simple turbulence model based on the mixing length hypothesis to account for the turbulence effects. A series of experimental measurements were conducted in the laboratory for the initial adjustment of the turbulence model and verification of the code. The second model is a one-dimensional far-field model which determines the change of the salt distribution in the pond gradient zone as a result of injection by coupling the near-field injection conditions to the pond geometry. This is implemented by distributing the volume fluxes obtained at the domain boundary of the near-field model, to the gradient layers of the same densities. The numerical predictions obtained by the two-region model was found to be in reasonable agreement with the experimental data.

scholarly journals An Analytical and Numerical Study of Magnetic Spring Suspension with Energy Recovery Capabilities

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3126 ◽  
Author(s):  
Yu Jia ◽  
Shasha Li ◽  
Yu Shi
Keyword(s):  
Energy Recovery ◽  
Numerical Study ◽  
Numerical Models ◽  
Limited Range ◽  
Paradigm Shifts ◽  
Restoring Force ◽  
Highly Nonlinear ◽  
Spring Mechanism ◽  
Paved Road ◽  
Rider Comfort

As the automotive paradigm shifts towards electric, limited range remains a key challenge. Increasing the battery size adds weight, which yields diminishing returns in range per kilowatt-hour. Therefore, energy recovery systems, such as regenerative braking and photovoltaic cells, are desirable to recharge the onboard batteries in between hub charge cycles. While some reports of regenerative suspension do exist, they all harvest energy in a parasitic manner, and the predicted power output is extremely low, since the majority of the energy is still dissipated to the environment by the suspension. This paper proposes a fundamental suspension redesign using a magnetically-levitated spring mechanism and aims to increase the recoverable energy significantly by directly coupling an electromagnetic transducer as the main damper. Furthermore, the highly nonlinear magnetic restoring force can also potentially enhance rider comfort. Analytical and numerical models have been constructed. Road roughness data from an Australian road were used to numerically simulate a representative environment response. Simulation suggests that 10’s of kW to >100 kW can theoretically be generated by a medium-sized car travelling on a typical paved road (about 2–3 orders of magnitude higher than literature reports on parasitic regenerative suspension schemes), while still maintaining well below the discomfort threshold for passengers (<0.315 m/s 2 on average).

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