Syamsul Rizal

Taylor's problem—influences on the spatial distribution of real and virtual amphidromes

Abstract Calculations are performed to examine the behavior of incident and reflected Kelvin waves, representing the tide, within a channel closed at one end—the Taylor (Proc. Lond. Math. Soc. 20 (2) (1921) 148) problem. Real or virtual (degenerate) amphidromic points may result, their displacement from the central axis of the channel being related to the tidal dissipation. Experiments are performed with the channel at different geographical latitudes and with varying friction. The influence on the spatial distribution of real and virtual amphidromic points is presented.

On the M2-tide of the Malacca Strait: A numerical investigation

In this paper, the M2-tide of the Malacca Strait is computed using a three-dimensional model based upon a semi-implicit numerical scheme. As results the regional distribution of amplitudes, phases, instantaneous velocities, tidal ellipses, residual currents and vertical current profiles at a few points are obtained. Furthermore the mass transport, the kinetic and potential energy, the dissipation of energy by bottom friction and horizontal eddy viscosity, the energy input and the energy balance are determined.

Current simulation in the Malacca Strait and part of South China Sea due to wind

The Malacca Strait (MS) and part of South China Sea (SCS) are simulated with a two-dimensional numerical model. The model covers in the domain 0.5° N – 5.5° N and 95.5° E – 105° E. The model solved the Navier-Stokes equations with the discretization Δx = Δy = 5 minutes and time step Δt = 50 seconds and we use Arakawa C-grid. The simulations are done for February 2010 and August 2010 based on the wind data derived from the National Centers of Environmental Prediction (NCEP) and open boundaries for sea level elevation obtained from Simple Oceanic Data Assimilation (SODA) v2.2.4. In February, strongly NE winds occur at SCS, whereas in MS weakly north wind from the north. In August, at SCS south wind occurs and in MS, SW wind direction is dominant in the northern part MS. The use of constants r = 0.038 generates the sea current velocity with the small results and far from the real situation. By using the constant r = 0.0025, the currents are greater about 50% compared to that of r = 0.038.

Current simulation in the Gulf of Thailand due to wind and sea level elevation

Gulf of Thailand (GoT) is a semi-enclosed waters lying between the South China Sea and Peninsula Malaysia. The aim of this study is to simulate the effects of wind with a two-dimensional numerical model in the GoT. In this study, the discretization of grid is Δx = Δy = 5 minute and Δt = 100 minutes (according to the CFL criterion), while the total simulation is 5 days. We use the same open boundaries values, i.e. H = 0.5 m. We test results by using the v wind variations of wind velocities, as follows: northeast (NE) wind (at the speed 2, 3, and 5 m/s) and southwest (SW) wind (at the speed 2, 3, and 5 m/s). The results show that by using the wind speed of 5 m/s, the current simulations achieve the better results.

Study of current circulation in the Northern Waters of Aceh

The northern waters of Aceh are directly adjacent to the Malacca Strait, the Andaman Sea, and the Indian Ocean. These waters are an important route in the activities of shipping, fishing and others. The study of current circulation was studied by using the 2D hydrodynamic models. The purpose of this study is to determine the current patterns during the Northeast (February 2016) and southwest (August 2016) monsoons. To generate the models, we use the wind force obtained from European Center for Medium-Range Weather Forecast (ECMWF) 2016. The results show that the current circulation generally follows the bathymetry pattern and monsoonal direction.