MITIGATING TSUNAMI DAMAGE BY PROMOTING GROUND EROSION

2020 ◽  
pp. 2150007
Author(s):  
Naoki Takegawa ◽  
Yutaka Sawada ◽  
Toshinori Kawabata
Keyword(s):  
Numerical Simulations ◽  
Expanded Polystyrene ◽  
New Method ◽  
Reduction Mechanism ◽  
Velocity Reduction ◽  
Tsunami Damage ◽  
Ground Material

To reduce the damage caused when a tsunami overflows coastal dikes, this study performs hydraulic experiments and numerical simulations and proposes a new method for slowing the tsunami by intentionally eroding parts of the ground. The effectiveness of the proposed method is assessed, velocity-reduction mechanism is clarified, and reduced tsunami velocity is predicted. Using crushed expanded polystyrene (EPS) as the ground material, vertical erosion is enhanced and a large depression is formed that changes the flow from supercritical to subcritical, thereby decelerating it. Assuming a constant tsunami overflow rate, the tsunami velocity after deceleration can be predicted with [Formula: see text] uncertainty.

scholarly journals Reversal Ventilation as a Method of Fire Hazard Mitigation in the Mines

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1755 ◽  
Author(s):  
Grzegorz Pach ◽  
Zenon Różański ◽  
Paweł Wrona ◽  
Adam Niewiadomski ◽  
Pavel Zapletal ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Fire Hazard ◽  
Full Range ◽  
Acceptable Level ◽  
New Method ◽  
Underground Mines ◽  
Operating Parameters ◽  
Smoke Control ◽  
Prevention Methods ◽  
Air Control

Reversal ventilation is one of prevention methods against fire hazard in underground mines, but it is not recommended for the mines where methane is present. The authors introduce the new method of reversal and by conducting numerical simulations they prove that it allows to keep methane at the acceptable level during miners escape. However, it requires connection between the subnetworks of the main ventilation fans. It was also shown, that by using the method some escape routes will be shortened. It is possible to apply this method in the mines where the fans and stoppings are fully controlled across the full range of their operating parameters. The findings are important for underground mines, as well as for surface facilities where air control or smoke control is managed by two or more fans.

AN EFFICIENT MULTI-SPIN CODING ALGORITHM FOR NEURAL NETWORKS

1991 ◽  
Vol 02 (02) ◽  
pp. 623-636 ◽  
Author(s):  
MARTIN NESCHEN
Keyword(s):  
Neural Networks ◽  
Numerical Simulations ◽  
High Speed ◽  
Large Scale ◽  
Effective Rate ◽  
Computational Effort ◽  
Local Fields ◽  
New Method ◽  
Coupling Matrix ◽  
Horizontal Structure

A new method for large-scale numerical simulations of neural networks is proposed which reduces the computational effort by incrementally updating the local fields and thus restricting the operations to flipped spins only. A highly optimized multi-spin algorithm is described employing words oriented along the columns of the coupling matrix unlike the horizontal structure in existing high-speed algorithms. An effective rate of 35*109 couplings/s on a Cray-YMP can be attained which is about five times as fast as best existing multi-spin implementations.

scholarly journals Inferring the dark matter velocity anisotropy to the cluster edge

2020 ◽  
Vol 500 (3) ◽  
pp. 3151-3161
Author(s):  
Jacob Svensmark ◽  
Steen H Hansen ◽  
Davide Martizzi ◽  
Ben Moore ◽  
Romaine Tessier
Keyword(s):  
Dark Matter ◽  
Numerical Simulations ◽  
Galaxy Cluster ◽  
Dynamical Property ◽  
Large Error ◽  
New Method ◽  
Bright Galaxy ◽  
X Ray ◽  
Velocity Anisotropy ◽  
Error Bars

ABSTRACT Dark matter (DM) dominates the properties of large cosmological structures such as galaxy clusters, and the mass profiles of the DM have been inferred for these equilibrated structures for years by using cluster X-ray surface brightnesses and temperatures. A new method has been proposed, which should allow us to infer a dynamical property of the DM, namely the velocity anisotropy. For the gas, a similar velocity anisotropy is zero due to frequent collisions; however, the collisionless nature of DM allows it to be non-trivial. Numerical simulations have for years found non-zero and radially varying DM velocity anisotropies. Here we employ the method proposed by Hansen & Piffaretti, and developed by Høst et al. to infer the DM velocity anisotropy in the bright galaxy cluster Perseus, to near five times the radii previously obtained. We find the DM velocity anisotropy to be consistent with the results of numerical simulations, however, still with large error bars. At half the virial radius, we find the DM velocity anisotropy to be non-zero at 1.7$\, \sigma$, lending support to the collisionless nature of DM.

scholarly journals A survey on numerical simulations of drag and heat reduction mechanism in supersonic/hypersonic flows

2019 ◽  
Vol 32 (4) ◽  
pp. 771-784 ◽  
Author(s):  
Xiwan SUN ◽  
Wei HUANG ◽  
Min OU ◽  
Ruirui ZHANG ◽  
Shibin LI
Keyword(s):  
Numerical Simulations ◽  
Hypersonic Flows ◽  
Reduction Mechanism

A Velocity Measurement Method Based on Scaling Parameter Estimation of a Chaotic System

2011 ◽  
Vol 18 (2) ◽  
pp. 275-282
Author(s):  
Lidong Liu ◽  
Jifeng Hu ◽  
Zishu He ◽  
Chunlin Han ◽  
Huiyong Li ◽  
...  
Keyword(s):  
Parameter Estimation ◽  
Numerical Simulations ◽  
Chaotic System ◽  
Velocity Measurement ◽  
Measurement Method ◽  
Chaotic Synchronization ◽  
New Method ◽  
Target Velocity ◽  
Scaling Parameter ◽  
Generating System

A Velocity Measurement Method Based on Scaling Parameter Estimation of a Chaotic SystemIn this paper, we propose a new method of measuring the target velocity by estimating the scaling parameter of a chaos-generating system. First, we derive the relation between the target velocity and the scaling parameter of the chaos-generating system. Then a new method for scaling parameter estimation of the chaotic system is proposed by exploiting the chaotic synchronization property. Finally, numerical simulations show the effectiveness of the proposed method in target velocity measurement.

The Control of Stochastic Resonance by Harmonic Signal

2011 ◽  
Vol 50-51 ◽  
pp. 559-563 ◽  
Author(s):  
Mei Li Zhang ◽  
Min Lin
Keyword(s):  
Numerical Simulations ◽  
Stochastic Resonance ◽  
Harmonic Signal ◽  
New Method ◽  
Potential Wells ◽  
Bistable Systems ◽  
The Asymmetry ◽  
Resonance Control ◽  
Double Well Potential

The symmetry in a double-well potential of bistable systems subject to the action of a harmonic signal is broken. By variation of the amplitude of a harmonic signal, the asymmetry of bistable systems can be effectively controlled, the transitions probability between the two potential wells is increased and has influence on the effect of stochastic resonance in bistable systems. Numerical simulations show that adjusting the amplitude of a harmonic signal can produce stochastic resonance or make stochastic resonance more intense in bistable systems. It is a new method for stochastic resonance control.

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