scholarly journals A NUMERICAL SIMULATION FOR TSUNAMIS DUE TO A LAND SLIDE

2020 ◽  
pp. 11
Author(s):  
Taro Kakinuma ◽  
Tsunakiyo Iribe
Keyword(s):  
Water Depth ◽  
Water Surface ◽  
Reduction Rate ◽  
Surface Displacement ◽  
Rigid Bodies ◽  
Two Dimensions ◽  
Tsunami Source ◽  
Experimental Result ◽  
Tsunami Height ◽  
Numerical Result

Tsunamis, generated by falling rigid bodies, have been numerically simulated using the MPS model, in the vertical two dimensions. The numerical result for the water surface displacement of the first wave is in harmony with the corresponding experimental result obtained using the cylinders. A tsunami component traveling toward the shore and running up the slope can be confirmed in the present cases. The tsunami height, immediately after the large circles enter the water, does not depend much on the offshore still water depth, while the tsunami-height reduction is suppressed, when the offshore still water depth is shallower. Conversely, the tsunami height, immediately after the small circles enter the water, increases as the offshore still water depth is shallower. Both the tsunami height, immediately after the falling bodies enter the water, and the reduction rate of tsunami height, are larger for the large circles than for the small circles. In the cases where the falling rigid bodies include both the large and small circles, the reduction rate of the water level near the tsunami source is larger, when the large circles are stacked on the offshore side at the initial condition.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/BEUWDCV_T5k

scholarly journals The Tsunami Wave Energy

2020 ◽  
Vol 18 (4) ◽  
pp. 39-53
Author(s):  
Andrey G. Marchuk
Keyword(s):  
Wave Energy ◽  
Water Surface ◽  
Tsunami Wave ◽  
Opposite Sign ◽  
Surface Displacement ◽  
Tsunami Source ◽  
Energy Radiation ◽  
Long Wave ◽  
Axis Length ◽  
Radiation Directivity

The basic formulae for calculating the moving long wave energy were derived and presented. The problems related to the energy counting in the course of numerical modeling of tsunami wave generation and propagation. Through a number of computational experiments, the wave energy radiation directivity of tsunami generated by an ellipsoidal source with a various axis length ratio was studied. The wave energy radiation directivity of the dipole tsunami source consisting of two ellipsoidal sources with opposite sign of the water surface displacement is considered.

Numerical Simulation of Cutting Force in High Speed Machining of Inconel 718

2020 ◽  
Vol 856 ◽  
pp. 43-49
Author(s):  
Santosh Kumar Tamang ◽  
Nabam Teyi ◽  
Rinchin Tashi Tsumkhapa
Keyword(s):  
Cutting Force ◽  
Inconel 718 ◽  
High Speed ◽  
Experimental Results ◽  
Machining Process ◽  
Experimental Result ◽  
Work Piece ◽  
High Speed Machining ◽  
Numerical Result ◽  
3D Software

Machining is one of the major manufacturing processes that converts a raw work piece of arbitrary size into a finished product of definite shape of predetermined size by suitably controlling the relative motion between the tool and the work. Lately, machining process is shifting towards high speed machining (HSM) from conventional machining to improve and efficiently increase production, and towards dry machining from excessive coolant used wet machining to improve economy of production. And the tools used are mostly hardened alloys to facilitate HSM. The work piece materials are continually improving their properties by emergence and development of newer and high resistive super alloys (HRSA). In this paper an attempt has been made to validate an experimental result of cutting force obtained by performing HSM on an HRSA Inconel 718, by comparing it with the numerical result obtained by simulating the same setting using DEFORM 3D software. Based on the comparison it is found that the simulated results exhibit close proximity with the experimental results validating the experimental results and the effectiveness of the software.

UNCERTAINTY ASSESSMENT OF TSUNAMI HEIGHT FOR FUTURE NANKAI-TONANKAI EARTHQUAKES USING STOCHASTIC TSUNAMI SOURCE MODELS

2021 ◽  
Vol 77 (2) ◽  
pp. I_181-I_186
Author(s):  
Takuya MIYASHITA ◽  
Kazuki KURATA ◽  
Tomohiro YASUDA ◽  
Nobuhito MORI ◽  
Tomoya SHIMURA
Keyword(s):  
Uncertainty Assessment ◽  
Tsunami Source ◽  
Tsunami Height ◽  
Source Models

scholarly journals Buried Depth of a Submarine Pipeline Based on Anchor Penetration

2019 ◽  
Vol 7 (8) ◽  
pp. 257
Author(s):  
Xueyuan Zhu ◽  
Qinglong Hao ◽  
Jie Zhang
Keyword(s):  
Numerical Simulation ◽  
Penetration Depth ◽  
Water Depth ◽  
Calculation Method ◽  
Water Surface ◽  
Submarine Pipeline ◽  
Projected Area ◽  
Actual Measurement ◽  
Calculation Results ◽  
The Relationship

Anchor penetration is an important issue involved in the study of submarine pipeline damage accidents. To explore the penetration of a ship’s anchor under certain conditions, this study investigated the motion and force of an anchor and formulated a calculation method for the bottoming speed of an anchor. Meanwhile, the depth of anchor penetration was calculated under different conditions according to bottoming speed through programming. Finally, the reliability of the calculation method for the penetration depth was verified by comparing the actual measurement and the numerical simulation. On the basis of the findings, the calculation results were further analyzed, and conclusions were derived regarding the relationship between anchor mass, the horizontal projected area of the anchor, the anchor height on the water surface, and water depth. The conclusions provide suggestions for the application of anchor penetration in terms of seabed depth with certain reference values.

Real-Time Tsunami Prediction System Using DONET

2017 ◽  
Vol 12 (4) ◽  
pp. 766-774 ◽  
Author(s):  
Narumi Takahashi ◽  
Kentaro Imai ◽  
Masanobu Ishibashi ◽  
Kentaro Sueki ◽  
Ryoko Obayashi ◽  
...  
Keyword(s):  
Real Time ◽  
Time Lag ◽  
Rupture Zone ◽  
Tsunami Source ◽  
Earthquake Rupture ◽  
Prediction System ◽  
Fault Models ◽  
Tsunami Height ◽  
Inundation Area ◽  
Selection Of

We constructed a real-time tsunami prediction system using the Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET). This system predicts the arrival time of a tsunami, the maximum tsunami height, and the inundation area around coastal target points by extracting the proper fault models from 1,506 models based on the principle of tsunami amplification. Since DONET2, installed in the Nankai earthquake rupture zone, was constructed in 2016, it has been used in addition to DONET1 installed in the Tonankai earthquake rupture zone; we revised the system using both DONET1 and DONET2 to improve the accuracy of tsunami prediction. We introduced a few methods to improve the prediction accuracy. One is the selection of proper fault models from the entire set of models considering the estimated direction of the hypocenter using seismic and tsunami data. Another is the dynamic selection of the proper DONET observatories: only DONET observatories located between the prediction point and tsunami source are used for prediction. Last is preparation for the linked occurrence of double tsunamis with a time-lag. We describe the real-time tsunami prediction system using DONET and its implementation for the Shikoku area.

NUMERICAL SIMULATION OF THE VAPOR FILM COLLAPSE BEHAVIOR AT VAPOR EXPLOSION WITH THREE-DIMENSIONAL LATTICE GAS THERMAL-HYDRAULIC AUTOMATA METHOD

2003 ◽  
Vol 17 (01n02) ◽  
pp. 189-192
Author(s):  
DAISUKE TOCHIO ◽  
YUTAKA ABE ◽  
YOSUKE MATSUKUMA ◽  
HIDEKI NARIAI
Keyword(s):  
Numerical Simulation ◽  
Phase Change ◽  
Lattice Gas ◽  
Three Dimensional ◽  
Experimental Result ◽  
Vapor Film ◽  
Lattice Gas Automata ◽  
Numerical Result ◽  
Collapse Behavior ◽  
Film Collapse

In order to clarify the dominant driving force of complex vapor film collapse behavior, numerical simulation is performed with three-dimensional fifteen-velocity lattice gas automata method. As the result, numerical result is qualitatively different from the experimental result. On the other hand, numerical simulation of vapor film collapse behavior is performed with three-dimensional fifteen-velocity lattice gas automata method including phase-change effect. As the result, numerical result is qualitatively similar to the experimental results. Comparison between the experimental result and the numerical result confirms that experimentally observed vapor film collapse behavior is dominated not by fluid motion but by phase change.

scholarly journals DISCONTINUOUS COMPOSITE WAVE ABSORBER STUDIES

1972 ◽  
Vol 1 (13) ◽  
pp. 104
Author(s):  
Anthony R. Fallon
Keyword(s):  
Water Depth ◽  
Water Wave ◽  
Water Surface ◽  
Wave Reflection ◽  
Wave Reflections ◽  
Stone Size ◽  
Test Conditions ◽  
Discontinuous Composite ◽  
Lower Slope ◽  
Upper Slope

An experimental study was conducted to determine the energy dissipation characteristics of a discontinuous wave absorber consisting of an impervious lower slope and a stone-filled upper slope. The purpose was to determine the wave energy absorption as a function of the incident wave parameters and the wave absorber geometry. Parameters varied were wavelength, wave height, lower and upper absorber slopes, berm depth and width, and stone size. For virtually all test conditions, a minimum wave reflection was found when the discontinuity (berm) depth was at one-quarter to one-half the water depth below the water surface. The overall wave absorption increased under the following conditions: an increase in horizontal berm width of up to five layers of stone; a decrease in the angle of the upper (stone-filled) slope when the berm depth is below one-fifth the water depth; and a decrease in the angle of the lower (impervious) slope when the berm depth is above one-half the water depth. The results should be useful where water wave reflections must be minimal and space is limited, such as in harbor walls or for hydraulic models.

scholarly journals Transitions and singularities during slip motion of rigid bodies

2018 ◽  
Vol 29 (5) ◽  
pp. 778-804 ◽  
Author(s):  
P. L. VÁRKONYI
Keyword(s):  
Coulomb Friction ◽  
Rigid Bodies ◽  
Two Dimensions ◽  
Multiple Point ◽  
Point Contacts ◽  
Stick Slip ◽  
Unilateral Contacts ◽  
Rigid Rod ◽  
Body Theory ◽  
Slip Motion

The dynamics of moving solids with unilateral contacts are often modelled by assuming rigidity, point contacts, and Coulomb friction. The canonical example of a rigid rod with one endpoint slipping in two dimensions along a fixed surface (sometimes referred to as Painlevé rod) has been investigated thoroughly by many authors. The generic transitions of that system include three classical transitions (slip-stick, slip reversal, and liftoff) as well as a singularity called dynamic jamming, i.e., convergence to a codimension 2 manifold in state space, where rigid body theory breaks down. The goal of this paper is to identify similar singularities arising in systems with multiple point contacts, and in a broader setting to make initial steps towards a comprehensive list of generic transitions from slip motion to other types of dynamics. We show that – in addition to the classical transitions – dynamic jamming remains a generic phenomenon. We also find new forms of singularity and solution indeterminacy, as well as generic routes from sliding to self-excited microscopic or macroscopic oscillations.

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