Accuracy Of Sub-models Research Articles

A Comparison of Soft Computing Methods for the Prediction of Wave Height Parameters

In the previous studies on the prediction of wave height parameters, only the significant wave height has been considered as the unknown parameter to be predicted. However, the other wave height parameters, which may be required for the design of coastal structures depending on their importance level, have been neglected. Therefore, in this study, novel soft computing methods were used to predict all wave height parameters required for the design of coastal structures. To this end, wave data were derived from a buoy located in Southwest Black Sea Coast. Then, Multi-layer Perceptron Neural Network (MLPNN) and Adaptive-Neuro Fuzzy Inference System (ANFIS) models were developed to predict wave height parameters. Various input combinations were selected to create seven different sub-models. These sub-models were applied using developed MLPNN and ANFIS models. Accuracy of sub-models were evaluated for each wave height parameters in terms of performance evaluation criteria. The results showed that the wave height parameters predicted by the MLPNN and ANFIS methods are similar and both methods yield results acceptable for design purposes. However, for maximum wave height, Hmax, ANFIS sub-model yields slightly better results.

A PREDICTIVE MODEL FOR SCOUR DEPTH OF COASTAL BUILDING FAILURES DUE TO TSUNAMIS

The 2011 Great East Japan Earthquake and Tsunami was one of the strongest earthquakes which generated a major tsunami in
 modern history. The tsunami disaster had an estimated cost of 16.9 trillion yen (US$ 217.3 billion) and affected the Coastal
 buildings, services, infrastructure and industrial sectors. Approximately 61% of damaged cost was from the building sector. A
 practical predictive scour depth model at seaward face was developed to highlight the scour failure of Coastal buildings in Miyagi,
 Fukushima and Iwate prefectures affected by the 2011 Great East Japan Earthquake and Tsunami. The predictive model for
 representative scour depth was developed in terms of various hydraulic, geometrical and soil properties affecting Coastal buildings.
 An analysis was undertaken to investigate the effectiveness of the authors’ predictive scour model against the existing models. The
 results of the authors’ proposed model suggested that the tsunami velocity played a significant role on tsunami-induced scour, other
 scour models such as Tonkin et al.’s model (2003) is reliant on the accuracy of sub models and hydrodynamic forces while the
 Colorado State University model as modified by Nadal et al. (2010) is reliant on the geometric parameter of the structure.

Large-eddy simulation of a bluff-body stabilized nonpremixed flame

Large-eddy simulations have been performed for a turbulent nonpremixed bluff-body stabilized CH 4:H 2 (50:50 vol.) flame at a Reynolds number of 15,800. The corresponding isothermal flow has also been computed. The Sydney bluff-body burner under consideration has been investigated experimentally by Masri and co-workers, who obtained velocity and scalar statistics. The focus of the current work is on flow and mixing effects with the thermochemistry evaluated using a steady-state laminar flamelet approach. The incompressible (low-Mach-number) governing equations for mass, momentum, and mixture-fraction have been solved on a structured cylindrical grid and resolution effects investigated using up to 3.643 × 10 6 nodes. The corresponding nonreactive case was resolved by 5.76 × 10 5 nodes, resulting in a resolution of more than 80% of the turbulence kinetic energy. The reacting case yields a resolution in excess of 75% on the finest grid—arguably sufficient to permit conclusions regarding the accuracy of submodels. Comparisons with experimental data show that for high resolutions comparatively good agreement is obtained for the flow field and for species other than nitric oxide. However, resolution effects are important and results obtained with 4.51 × 10 5 nodes show that a resolution of less than 70% of the turbulent kinetic energy is insufficient in the context of the Smagorinsky subgrid model combined with the dynamic procedure of Germano. The latter result is consistent with the analysis of Pope.