Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Debris-flow functioning and their contribution to sedimentary budgets : the Peynin subcatchment of the Guil River (Upper Queyras, Southern French Alps)

Viel V., Fort M., Lissak C., Graff K., Carlier B., Arnaud-Fassetta G., Cossart E., Madelin M.

Landform Analysis

2018

Vol. 36

71--84

The Peynin catchment (15 km2) is prone to catastrophic floods (June 1957 – Recurrence Interval R.I.>100 yr), June 2000 (R.I.-30 yr) with serious damages to infrastructure and buildings located at the outlet. In this paper, PIT tags tracers and Vensim modelling software are used to better assess the sediment delivery unsteadiness, and more specifically to evaluate the respective role of geomorphological processes on sediment supply during flood event. For the last 20 years, our results highlight a significant variability in sediment delivery from a tributary to another one. According to our studies, we suppose that two torrential tributaries of the Peynin river, the Peyronnelle and Three Arbres subcatchments (<2 km2, representing <15% of the Peynin catchment area) are responsible of 80% of the sediments observed at the outlet of the catchment. Several processes take a part of these sediment transfers, but the efficiency of the sediment cascade in this catchment can be explained by a strong connectivity between sediment erosion area and the main channel of the catchment. Debris and torrential flows triggered during high intensity meteorological event are actually effectively coupled in space and time and guarantee an important sediment supply able to reload the downstream part of the sediment cascade. Recent climate trends, marked by extremes, suggest consequently more damaging events to come, in a context of increasing vulnerable assets.

Charakterystyka hydrodynamiczna mieszanego płynu uzyskana metodą LDA/PDA

Sedivy V., Ditl P., Severa M., Fort M., Rieger F.

Prace Wydziału Inżynierii Chemicznej i Procesowej Politechniki Warszawskiej

1999

Vol. 25, z. 1-3

247-251

Authors recently developed and applied new experimental LDA/PDA technique which enables a direct measurement of local particle and fluid velocities. From such measurements mean and fluctuation velocities have been evaluated. Measurement has been performed in a baffled vessel agitated with pitched six-blade turbine. This paper reports velocity profiles related to liquid phase. Axial, radial and tangential mean and fluctuation velocity profiles have been evaluated in dimensioniess form and were well correlated by Tshebychew polynomials. Results of fluctuation velocities in all three directions proved the existence of isotropic turbulence m the most of vessel volume. Paper brings comparison of axial mean velocity components measured by various authors on the outlet of the pitched blade impellers.