scholarly journals A numerical study on precipitation over the western coastal area of Sumatra Island

2020 ◽  
Author(s):  
Ryosuke Okugawa ◽  
Kazuaki Yasunaga ◽  
Atsushi Hamada
2020 ◽  
Author(s):  
Ryosuke Okugawa ◽  
Kazuaki Yasunaga ◽  
Atsushi Hamada

2019 ◽  
Vol 7 (10) ◽  
pp. 337 ◽  
Author(s):  
Francesco Gallerano ◽  
Giovanni Cannata ◽  
Federica Palleschi

A three-dimensional numerical study of the hydrodynamic effect produced by a system of submerged breakwaters in a coastal area with a curvilinear shoreline is proposed. The three-dimensional model is based on an integral contravariant formulation of the Navier-Stokes equations in a time-dependent curvilinear coordinate system. The integral form of the contravariant Navier-Stokes equations is numerically integrated by a finite-volume shock-capturing scheme which uses Monotonic Upwind Scheme for Conservation Laws Total Variation Diminishing (MUSCL-TVD) reconstructions and an Harten Lax van Leer Riemann solver (HLL Riemann solver). The numerical model is used to verify whether the presence of a submerged coastal defence structure, in the coastal area with a curvilinear shoreline, is able to modify the wave induced circulation pattern and the hydrodynamic conditions from erosive to accretive.


Atmosphere ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. 51 ◽  
Author(s):  
Zixuan Yang ◽  
Antoni Calderer ◽  
Sida He ◽  
Fotis Sotiropoulos ◽  
James Doyle ◽  
...  

2017 ◽  
Vol 145 (9) ◽  
pp. 3745-3761 ◽  
Author(s):  
Satoru Yokoi ◽  
Shuichi Mori ◽  
Masaki Katsumata ◽  
Biao Geng ◽  
Kazuaki Yasunaga ◽  
...  

This study analyzes data obtained by intensive observation during a pilot field campaign of the Years of the Maritime Continent Project (Pre-YMC) to investigate the diurnal cycle of precipitation in the western coastal area of Sumatra Island. The diurnal cycle during the campaign period (November–December 2015) is found to have a number of similarities with statistical behavior of the diurnal cycle as revealed by previous studies, such as afternoon precipitation over land, nighttime offshore migration of the precipitation zone, and dependency on Madden–Julian oscillation (MJO) phase. Composite analyses of radiosonde soundings from the Research Vessel (R/V) Mirai, deployed about 50 km off the coast, demonstrate that the lower free troposphere starts cooling in late afternoon (a couple of hours earlier than the cooling in the boundary layer), making the lower troposphere more unstable just before precipitation starts to increase. As the nighttime offshore precipitation tends to be more vigorous on days when the cooling in the lower free troposphere is larger, it is possible that the destabilization due to the cooling contributes to the offshore migration of the precipitation zone via enhancement of convective activity. Comparison of potential temperature and water vapor mixing ratio tendencies suggests that this cooling is substantially due to vertical advection by an ascent motion, which is possibly a component of shallow gravity waves. These results support the idea that gravity waves emanating from convective systems over land play a significant role in the offshore migration of the precipitation zone.


Author(s):  
Joan Goldstein ◽  
Yakov Tokar ◽  
Yakov Balmor ◽  
Ed Glaser ◽  
Pinhas Alpert

2011 ◽  
Vol 255-260 ◽  
pp. 2313-2317
Author(s):  
Ruey Syan Shih

Numerical investigations of multiphase irregular wave field are presented by using the BEM, which incorporates the interaction between incoming wave and reflected wave in the coastal area. This study discusses the case of multi-component wave generation using the 2D-NWT, which incorporates the wave-wave interactions between various conditions of incoming waves and high frequency reflected waves, including the variation of wave field and particle trajectory. The surf beats in the surf zone is mainly the cause of the cross-shore motion, and the generations of high frequency harmonics waves, these phenomena will be study accordingly in this preliminary study for the modeling of oscillations cause by surf beat and back swash, the generation of high frequency multi-phase reflected wave are carried out to investigate the deformation of wave profile, wave field and particle path-line.


Author(s):  
Feddy Adong ◽  
Anne-Claire Bennis ◽  
Dominique Mouazé

A numerical study is carried out to determine the parameters controlling the filling of a bore hole in Alderney Race. Our final goal is to identify the configuration minimizing the filling. We performed a one-way coupling between a coastal circulation model and a discrete element model for that purpose. Simulations used spherical particles and a monopile technology. We show that: as long as the distance between the hole and the residuals remains smaller than twenty meters, the flow direction plays a negligible role; interaction between moving particles and bottom roughness leads to a slight increase of the filling; the impact of ambient sediments strongly depends on seabed morphology and current effects.


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