Search

Posidonia oceanica meadows are considered to be of high importance to the environmental conservation in the Mediterranean Sea, supporting a highly biodiverse habitat and protecting from coastal erosion. In the CIEM wave flume of LIM/UPC (Barcelona, Spain) large scale experiments have been conducted for measuring wave attenuation, transmission and energy dissipation over artificial P. oceanica in intermediate and shallow waters. The effects of submergence ratio hs/D (hs = height of seagrass, D = water depth) and seagrass density (number of stems per squared meter) on the above characteristics are investigated. Mean velocities above and within the simulated P. oceanica are measured and the wave induced flow within the seagrass, which influences processes such as nutrient uptake, waste removal and larval dispersion, is estimated. A meadow with a total length of 10.70 m was constructed using polypropylene artificial plants. Measurements of wave height at different locations along the meadow indicate attenuation of waves for three different submergence ratios (hs/D), two seagrass densities (stems/m2) and various wave conditions. Results are also analysed with regard to the wave induced flow within the field and the effects of hs/D and seagrass density on mean flow characteristics are investigated based on measurements of mean velocities taken within the meadow., Peer Reviewed, Postprint (published version)

This is the final version of a report on review on flood hazard mapping., Floodsite

This is the final version of a report on review on flood hazard mapping., Floodsite

The design of structures to be built in the nearshore region generally involves the evaluation of different possible layouts, under the effects of local wave and cunents conditions, with the aim of minimizing costs and maximizing the desired results. In particular the design of lowcrested structures involves optimisation of several parameters, which influence both the position, and the shape of the structures. The possible layout of the structures to be designed can be tested experimentally in wave tanks and wave flumes using adequate scale models. An alternative and attractive procedure is to employ suitable numerical and mathematical models. In principle, a very advanced numerical model, able to conectly simulate all the nearshore phenomena (turbulence, waves, currents, sediment transport, etc.) could be equivalent or even superior to a physical model. In practice, the numerical models currently employed in engineering activities, use several assumptions and simplifications: the phenomena that can be simulated strictly depend on the governing equations solved by the model. Indeed, the great advantage of numerical and mathematica! models is that their application is usually much less expensive than physical ones: it is certainly more economie to modify a computer file describing the bathymetry of the area under investigation than rebuild a physical model layout. This report is structured into two discrete sections, the first one contributed by AUTh and the second one by UR3. In the first section a 2DH higher-order Boussinesq-type model combined with a porous flow model, developed tor simulating flow around porous submerged structures is presented. On the other hand, in the second section enhancements on the applicability of Boussinesq-type equations (BTE) into the surf and swash zone are described., Delos

The design of structures to be built in the nearshore region generally involves the evaluation of different possible layouts, under the effects of local wave and cunents conditions, with the aim of minimizing costs and maximizing the desired results. In particular the design of lowcrested structures involves optimisation of several parameters, which influence both the position, and the shape of the structures. The possible layout of the structures to be designed can be tested experimentally in wave tanks and wave flumes using adequate scale models. An alternative and attractive procedure is to employ suitable numerical and mathematical models. In principle, a very advanced numerical model, able to conectly simulate all the nearshore phenomena (turbulence, waves, currents, sediment transport, etc.) could be equivalent or even superior to a physical model. In practice, the numerical models currently employed in engineering activities, use several assumptions and simplifications: the phenomena that can be simulated strictly depend on the governing equations solved by the model. Indeed, the great advantage of numerical and mathematica! models is that their application is usually much less expensive than physical ones: it is certainly more economie to modify a computer file describing the bathymetry of the area under investigation than rebuild a physical model layout. This report is structured into two discrete sections, the first one contributed by AUTh and the second one by UR3. In the first section a 2DH higher-order Boussinesq-type model combined with a porous flow model, developed tor simulating flow around porous submerged structures is presented. On the other hand, in the second section enhancements on the applicability of Boussinesq-type equations (BTE) into the surf and swash zone are described., Delos

The split hand-split foot (SHSF) malformation affects the central rays of the upper and lower limbs. It presents either as an isolated defect or in association with other skeletal or non-skeletal abnormalities. An autosomal SHSF locus (SHFM1) was previously mapped to 7q22.1. We report the mapping of a second autosomal SHSF locus to 10q24-->25. A panel of families was tested with 17 marker loci mapped to the 10q24-->25 region. Maximum lod scores of 3.73, 4.33 and 4.33 at a recombination fraction of zero were obtained for the loci D10S198, PAX2 and D10S1239, respectively. An 19 cM critical region could be defined by haplotype analysis and several genes with a potential role in limb morphogenesis are located in this region. Heterogeneity testing indicates the existence of at least one additional autosomal SHSF locus.

The three - dimensional flow in sharp bends is computed by solving the fully elliptic three - dimensional Navier - Stokes equations in conjunction with a k - Epsilon model of turbulence. Computed isovelocity patterns before and after the sharp bend and recirculation lengths are compared with experimental measurements taken using Laser Doppler Anemometry. In general good agreement is obtained although refinements in the turbulence modelling can improve the predictions. The computational results show that the recirculating region to depends strongly on the inlet velocity profile. Finally an increase of the aspect ratio of the duct indicates an increase of the region of the recirculation., This article is from 'CFD Techniques for Propulsion Applications Panel Symposium (77th) Held in San Antonio, Texas on 27-31 May 1991 (Les Techniques de l'Aerodynamique Numerique pour les Applications aux Propulseurs)', AD-253 647, p35-1 thru p35-12.