| ATTRIBUTE | VALUE |
|---|
| type | A |
| database id | 7351 |
| title | The occurrence of s-shaped velocity profiles in gravel-bed river flows |
| authors | Mario J. Franca, Urlich Lemmin |
| pages | 29 — 41 |
| full text link | http://www.ibwpan.gda.pl/storage/app/media/ahem/ahem56str029.pdf |
| keywords | field measurements, gravel-bed river flows, velocity profiles, depth-averaged velocity |
| affiliations | - Departmento de Engenharia Civil Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa Quinta da Torre, 2829-516 Caparica, Portugal, e-mail: mfranca@dec.uc.pt
- Laboratoire d’Hydraulique Environnementale (LHE), Ecole Polytechnique Federale de Lausanne CH 1015 Lausanne, Switzerland, ulrich.lemmin@epfl.ch
|
| abstracts | Based on ADVP field measurements, we discuss velocity profiles observed in two shallowgravel-bed rivers with low blockage ratio. In these flows, log-shaped profiles and s-shapedprofiles simultaneously exist, indicating the possibility of 3D flow inside the roughnesslayer. However, a quasi-2D layer is generally found in an intermediate region of the flowoutside the roughness layer. Therefore a best-fit log-law approach may lead to estimates ofa roughness parameter which are reasonably correlated with the local flow resistance. Abovea certain limit of the ratio roughness parameter/water depth (≈ 0.6 from our measurements),the velocity distribution in the lower regions corresponds to an s-shaped profile. We alsoinvestigate the velocity distribution throughout the flow depth and conclude that the meanof the velocity profile roughly occurs at a normalized distance of the riverbed of 0.40, forboth log- and s-shaped profiles. |
| attributes | [reviewed] [scientific] |
| language | en |
| ATTRIBUTE | VALUE |
|---|
| type | A |
| database id | 7352 |
| title | A Lagrangian finite element analysis of gravity waves in water of variable depth |
| authors | Staroszczyk R. |
| pages | 43 — 61 |
| notes | Maszynopis w opracowaniu wewnętrznym Tp4170 |
| full text link | http://www.ibwpan.gda.pl/storage/app/media/ahem/ahem56str043.pdf |
| keywords | gravity water wave, variable water depth, transient problem, Lagrangian formulation, finite element method |
| affiliations | - Institute of Hydro-Engineering PAS, ul. Kościerska 7, 80-328 Gdańsk-Oliwa, Poland, e-mail: rstar@ibwpan.gda.pl
|
| abstracts | The paper is concerned with the problem of gravitational wave propagation in water ofvariable depth. The problem is formulated in the Lagrangian description, and the ensuingequations are solved numerically by a finite element method. In computations a convectingmesh that follows the material fluid particles is used. As illustrations, results of numericalsimulations carried out for plane gravity waves propagating over bottoms of simple geometryare presented. For parameters typical of a laboratory flume, the transformation of a transientwave, generated by a single movement of a piston-like wave maker, is investigated. Theresults show the evolution of the free-surface elevation, displaying steepening of the waveover sloping beds and its gradual attenuation in regions of uniform depth. |
| attributes | [reviewed] [scientific] |
| language | en |
| points | 4 |
| ATTRIBUTE | VALUE |
|---|
| type | A |
| database id | 7353 |
| title | On the description of long water waves in material variables |
| authors | Szmidt K., Hedzielski B. |
| pages | 63 — 83 |
| notes | Maszynopis w opracowaniu wewnętrznym Tp4169 |
| full text link | http://www.ibwpan.gda.pl/storage/app/media/ahem/ahem56str063.pdf |
| keywords | long wave, shallow water, unsteady motion, sloping beach |
| affiliations | - Institute of Hydro-Engineering of the Polish Academy of Sciences (IBW PAN), ul. Waryńskiego 17, 71-310 Szczecin, Poland, email: jks@ibwpan.gda.pl
|
| abstracts | Shallow water equations formulated in material variables are presented in this paper. In themodel considered, a three-dimensional physical problem is substituted by a two-dimensionalone describing a transformation of long waves in water of variable depth. The latter isobtained by means of the assumption that a vertical column of water particles remainsvertical during the entire motion of the fluid. Under the assumption of small, continuousvariation of the water depth, the equations for gravity waves are derived through Hamilton’sprinciple formulated in terms of the material coordinates. This formulation ensures theconservation of mechanical energy. The approximation depends on the wave parameters aswell as on the bed bathymetry. The latter may influence a solution of the model decisively;thus, one should be careful in applying the description to complicated geometries of fluiddomains encountered in engineering practice. |
| attributes | [reviewed] [scientific] |
| language | en |
| points | 4 |
| ATTRIBUTE | VALUE |
|---|
| type | A |
| database id | 7090 |
| title | Strains in sand due to cyclic loading in triaxial conditions |
| authors | Sawicki A., Mierczyński J., Świdziński W. |
| pages | 85 — 98 |
| full text link | http://www.ibwpan.gda.pl/storage/app/media/ahem/ahem56str085.pdf |
| keywords | cyclic loadings, granular soils, premanent strains, triaxial conditions |
| affiliations | - Institute of Hydro-Engineering PAS, ul. Kościerska 7, 80-328 Gdańsk-Oliwa, Poland, e-mail: as@ibwpan.gda.pl
|
| abstracts | The experimental results dealing with the cyclic loading of sand samples in triaxial conditionsare presented. These results show the development of both the volumetric and deviatoricpermanent strains due to a large number of loading cycles. The analysis of experimentaldata has led to the formulation of semi-empirical constitutive equations, expressed in theincremental form, for these strains as functions of the cyclic shear stress amplitude, numberof loading cycles and the initial stress state, around which the cyclic shearing takes place. |
| attributes | [reviewed] [scientific] |
| language | en |
| points | 4 |
| ATTRIBUTE | VALUE |
|---|
| type | A |
| database id | 7350 |
| title | Coastal processes at selected shore segments of south Baltic Sea and Gulf of Tonkin (South China Sea) |
| authors | Ostrowski R., Pruszak Z., Różyński G., Szmytkiewicz M., Ninh Van P., Quynh D. N., Lien T. N. V. |
| pages | 3 — 28 |
| full text link | http://www.ibwpan.gda.pl/storage/app/media/ahem/ahem56str003.pdf |
| keywords | non-tidal and tidal coast, waves and currents, sediment transport, morphodynamics |
| affiliations | - Institute of Hydro-Engineering of the Polish Academy of Sciences (IBW PAN), Kościerska 7, 80-328 Gdańsk, Poland, email: rafi@ibwpan.gda.pl
- Institute of Mechanics, Center for Marine Environment, Survey, Research and Consultation (CMESRC), 264 Doi Can, Hanoi, Vietnam
|
| abstracts | The paper presents a comparative analysis of physical processes occurring at two differentcoasts, which belong to two different geographic zones, namely a subtropical region exposedto monsoons and typhoons and a region of temperate climate with ice-snowy winter season.The former coast comprises sandy shores nearby Lubiatowo and the Hel Peninsula, locatedat the south Baltic Sea in Poland. The shore at Lubiatowo is relatively stable in the long run,while the shore along Hel Peninsula is mostly vulnerable to erosion and strongly protectedby use of various measures (groins, seawall and artificial beach nourishment). The secondsite is the eroded (and partly protected by dikes) coast at Hai Hau in the Gulf of Tonkin(the South China Sea, Vietnam). This shore segment is built of mixtures of sandy andcohesive material, comprising both marine sands and river-borne sediments which nourishthe coastal zone at the Red River mouth, located northwards of the Hai Hau beach. Thepresent analysis is focused on differences and similarities of hydro- and morphodynamicsbetween the above coastal zones in various time and spatial scales. The analysis shows thatregional climatic and environmental conditions, associated with geographical zones, playa key role in dynamic evolution of the coastal regions and necessitate different engineeringactivities against erosion and flooding. |
| attributes | [reviewed] [scientific] |
| language | en |
| points | 4 |