Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Coupling numerical models for wave propagation in the MOIA packagePublication . Santos, João Alfredo; Guilherme, L.; Fortes, C. J.; Pinheiro, L.; Simões, A.Sea wave action is a key factor for several aspects of port activities. Numerical models for wave forecasting at a regional level can produce quite accurate estimates of the sea state characteristics offshore a given port. There is a research project going on, code-named MOIA, that aims at developing an integrated toot to support the management of port activities by taking into account the effects of waves on some of those activities. To characterize sea waves inside a given port use is made of a set of coupled models that propagate the values that were measured or predicted off the port. The starting point is a tool developed at LNEC, SOPRO, which incorporates several of such numerical models. The paper describes the progress done so far in the coupling of the several numerical models that enable the propagation of the sea-state characteristics forecast off the Praia da Vitoria port (Terceira, Azores) up to the port terminals.
- In-situ and model wave characterization at the Alfeite beachPublication . Capitão, R.; Fortes, C. J.; Santos, João Alfredo; Pinheiro, L.In the framework of a research project entitled "BERNA", a methodology was devised to characterize the wind waves at the Alfeite beach, in the inner estuary of the Tagus river, by making in-situ measurements and using a numerical wave propagation model. With this goal in mind, a number of in-situ measurements were made, for a few selected positions in front of the Alfeite beach, at three different days, using resistive wave gauges and pressure transducers. During this period, a number of wave records, with different durations, were obtained and analyzed. Although these measurements proved to be useful to give a good insight of the main characteristics of the wind waves that might occur at that particular location, they cannot give a general characterization of the wind wave climate on the Tagus estuary, especially at the Alfeite beach, since they are a small number and are limited to a few positions only. To overcome these shortcomings, the SWAN numerical model was used to account for wave generation, propagation, attenuation and non linear interactions between wave and current phenomena in the whole estuary, in particular in the Alfeite beach. In this way, the model is applied to the same conditions of wind and tide observed on measurement days. This paper summarizes the wave characterization work performed under the BERNA project. A comparison of the SWAN results to wave parameters from wave records obtained in front of Alfeite beach is made and discussed.
- Implementation of partial reflection boundary conditions in wave propagation model BOUSSIIWPublication . Pinheiro, L.; Fortes, C. J.; Santos, João Alfredo; Walkley, M.This paper describes the implementation of a new boundary conditions in the BOUSSIIW model (BOUSSinesq model with Internal Irregular Wave generation). BOUSSIIW is a finite element numerical model for wave propagation in near shore regions that is able to describe the wave field outside and inside harbours and sheltered zones. It is based upon the extended Boussinesq equation derived by Nwogu. These equations describe the nonlinear evolution of waves over a sloping impermeable bottom and are able to reproduce some of the most important physical effects associated with the nonlinear wave transformation in near shore regions. Their range of validity extends from shallow up to intermediate water depths. Monochromatic and irregular waves can be generated by the model using the source function method. The two boundary conditions available were full reflection or full absorption. A new partial reflection boundary condition is implemented. The model is validated with a simple test case. Reflection coefficients obtained with BOUSSIIW were compared to widely used empirical formula, enabling the assessment of the new condition's performance. The results showed that the partial reflection boundary condition implemented was able to absorb energy from the wave and reflect some part back to the numerical domain.