| ATTRIBUTE | VALUE |
|---|
| type | A |
| database id | 7629 |
| title | Improved HLL scheme for 1D dam-break flows over complex topography |
| authors | Xinya Ying, Sam S. Y. Wang |
| pages | 31 — 41 |
| full text link | http://www.ibwpan.gda.pl/storage/app/media/ahem/ahem57str031.pdf |
| keywords | dam-break flow, HLL approximate Riemann solver, finite volume method, Saint Venant equations |
| affiliations | - National Center for Computational Hydroscience and Engineering, The University of Mississippi, MS38677, USA, e-mail: ying@ncche.olemiss.edu
|
| abstracts | It has been discovered that the shallow water model based on approximate Riemann solvers
can produce unrealistic flows in the case of uneven topography and inaccurate solutions of
discharge near hydraulic jumps. To overcome these deficiencies, we proposed a new approach
to implement the HLL Riemann solver for open channel flows, including: (1) adopting a form
of Saint Venant equations which have only one source term representing driving forces; (2)
defining discharge at interface and evaluating it according to the flux obtained by the HLL
Riemann solver. In this paper, the performance of this new method is evaluated by means of
dam-break flows over a channel with triangular cross-section and a natural river valley with
complex topography, respectively. Comparisons of computed results with analytic solutions
and data measured from the physical model show that the proposed method is capable of
satisfactorily reproducing dam-break flows over complex topography. |
| attributes | [reviewed] [scientific] |
| language | en |
| ATTRIBUTE | VALUE |
|---|
| type | A |
| database id | 7630 |
| title | Gravity- and turbulence-dominated sediment motion in the clear-water scour process at a vertical-wall abutment in pressurized flow |
| authors | Alessio Radice, Francesco Ballio, Chau K. Tran |
| pages | 43 — 59 |
| full text link | http://www.ibwpan.gda.pl/storage/app/media/ahem/ahem57str043.pdf |
| keywords | abutment scour, sediment kinematics, turbulence, sliding |
| affiliations | - Alessio Radice, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy, e-mails: alessio.radice@polimi.it, francesco.ballio@polimi.it, chau.tran@mail.polimi.it
|
| abstracts | Results on the motion of sediment particles on the bottom of the erosion hole are shown
for a clear-water scour experiment with a vertical-wall abutment. The paper presents an
investigation of particle kinematics starting from the division of the grain instantaneous
movements into two populations, namely the “turbulence-dominated” events (those in which
the particle motion is triggered by the turbulent flow field) and the “gravity-dominated”
events (those in which the particles slide along the slopes of the scour hole due to geotechnical
instability). Attention is focused on the well developed stages of the erosion process.
For such experimental times, the action of the principal vortex system is particularly evident
because the latter is not much stretched along the direction of the mean flow deviation, thanks
to the increased flowing area. At the same time, the temporal unsteadiness of the vortices
lets a bimodal behaviour of the sediments to emerge. A relevant difference has been found
between the dynamics of gravity-dominated and turbulence-dominated events. In addition,
it was found that the presence of geotechnical effects in the erosion hole may significantly
alter the scour rate. Potential implications of the present results for the modelling of local
scour processes are described. |
| attributes | [reviewed] [scientific] |
| language | en |
| ATTRIBUTE | VALUE |
|---|
| type | A |
| database id | 7455 |
| title | Simulation of dam-break flow by a corrected smoothed particle hydrodynamics method |
| authors | Staroszczyk R. |
| pages | 61 — 79 |
| notes | Maszynopis w oprac. Tp4204 |
| full text link | http://www.ibwpan.gda.pl/storage/app/media/ahem/ahem57str061.pdf |
| keywords | Dam-break problem, free-surface flow, meshfree Lagrangian method, smoothed particle hydrodynamics |
| affiliations | - Institute of Hydro-Engineering, Polish Academy of Sciences, ul. Kościerska 7, 80-328 Gdańsk, Poland, e-mail: rstar@ibwpan.gda.pl
|
| abstracts | The paper deals with numerical modelling of water flow which is generated by the break
of a dam. The problem is solved by applying a smoothed particle hydrodynamics (SPH)
method in which standard smoothing kernel functions are corrected in such a way that
so-called linear reproducing conditions for kernel approximations and their gradients are
satisfied. The proposed SPH model has been used to simulate a two-dimensional problem
of the collapse of a water column inside a rectangular tank. The simulations illustrate the
formation and subsequent propagation of a wave over the horizontal plane. It is shown
that the model predictions of the changes of the advancing wave-front position, and of the
changes of the free surface elevation of water, compare well with experimental data. Also,
the results obtained with the corrected SPH method are compared with those given by the
standard SPH method with no kernel correction. In addition, an impact of the surging wave
against a vertical rigid wall is illustrated. |
| attributes | [reviewed] [scientific] |
| language | en |
| points | 6 |