Browsing by Author "Omira, R."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Comparison between MUSCL and MOOD techniques in a finite volume well-balanced code to solve SWE. The Tohoku-Oki, 2011 examplePublication . Reis, C.; Figueiredo, J.; Clain, S.; Omira, R.; Baptista, Maria Ana Carvalho Viana; MIRANDA, JORGE MIGUELNumerical modelling is a fundamental tool for scenario-based evaluation of hazardous phenomena such as tsunami. Nevertheless, the numerical prediction highly depends on the tool quality and therefore the design of efficient numerical schemes that provide robust and accurate solutions still receives considerable attention. In this paper, we implement two different second-order finite volume numerical schemes deriving from an a priori or an a posteriori limitation procedure and we compare their efficiency in solving the non-conservative shallow-water equations. The numerical schemes assessed here are two variants of the a priori Monotonic Upstream-Centred Scheme for Conservation Laws (MUSCL) and the recent a posteriori multidimensional optimal order detection (MOOD) technique. We benchmark the numerical code, equipped with MUSCL and MOOD techniques, against: (1) a 1-D stationary problem with non-constant bathymetry to assess the second-order convergence of the method when a smooth analytical solution is involved; (2) a 1-D dam-break test to show its capacity to deal with irregular and discontinuous bathymetry in wet zones; and (3) using a simple 1-D analytical tsunami benchmark, single wave on a sloping beach', we show that the classical 1-D shallow-water system can be accurately solved by the second-order finite volume methods. Furthermore, we test the performance of the numerical code for the real-case tsunami of Tohoku-Oki, 2011. Through a set of 2-D numerical simulations, the 2011 tsunami records from both DART and GPS buoys are checked against the simulated results using MUSCL and MOOD. We find that the use of the MOOD technique leads to a better approximation between the numerical solutions and the observations than the MUSCL one. MOOD allows sharper shock capture and generates less numerical diffusion, suggesting it as a promising technique for solving shallow-water problems.
- Probabilistic and deterministic estimates of near-field tsunami hazards in northeast OmanPublication . El-Hussain, I.; Omira, R.; Al-Habsi, Z.; Baptista, Maria Ana Carvalho Viana; Deif, A.; Mohamed, A. M. E.Tsunamis generated along the Makran subduction zone (MSZ) threaten the Sur coast of Oman, according to deterministic and probabilistic analyses presented here. A validated shallow water numerical code simulates the source-to-coast propagation and quantifies the coastal hazard in terms of maximum water level, flow depth, and inundation distance. The worst-case source assumed for the eastern MSZ is a thrust earthquake of Mw 8.8. This deterministic scenario produces simulated wave heights reaching 2.5 m on the Sur coast leading to limited coastal inundation extent. Because Oman adjoins the western MSZ, the probabilistic analysis includes the effect of this segment also. The probabilistic analysis shows onshore inundations exceeding 0.4 km northwest of Sur where flow depths are likely to exceed 1 m in 500 years. Probability analysis shows lesser inundation areas with probability of exceeding 1 m flow depth up to 80% in 500-year exposure time. Teletsunamis are excluded from these analyses because far-field waves of the 2004 Indian Ocean tsunami did not impact the Sur coast. Also excluded for simplicity are tsunamis generated by submarine slides within or near MSZ rupture areas. The results of this research provide essential information for coastal planning, engineering and management in terms of tsunami hazard and an essential step toward tsunami risk reductions in the northwest Indian Ocean.