References of "Silvestri, Aurélien"
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See detailStepped spillway Downstream of a Piano Key Weir - Critical length for uniform flow
Silvestri, Aurélien ULg; Pirotton, Michel ULg; Erpicum, Sébastien ULg et al

in Bung, Daniel B.; Pagliara, Stefano (Eds.) International Workshop on Hydraulic Design of Low-Head Structures (2013)

Recent researches showed the rapid aeration of the flow downstream of piano key weirs. This could be related to the specific geometric features of the structure, creating several interacting flows and ... [more ▼]

Recent researches showed the rapid aeration of the flow downstream of piano key weirs. This could be related to the specific geometric features of the structure, creating several interacting flows and jets downstream. In order to validate this assumption, an experimental research has been carried out at the Laboratory of Engineering Hydraulics, University of Liège. The main objective of the study was to an-alyze the energy dissipation occurring in skimming flow conditions on a stepped spillway downstream of a piano key weir (PKW). Comparison with energy dissipation on a stepped spillway downstream of a standard ogee crested weir has been performed. An indirect method has been used to determine the resid-ual energy at the spillway toe. The results show that uniform flow conditions are reached faster on a stepped spillway downstream of a PWK compared to the length needed downstream of a standard ogee crested weir. Extrapolation of the results to prototype flow conditions is also discussed with regards to scale effects influence. [less ▲]

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See detailComparative analysis of the energy dissipation on a stepped spillway downstream of a Piano Key Weir
Silvestri, Aurélien ULg; Archambeau, Pierre ULg; Pirotton, Michel ULg et al

in Erpicum, Sébastien; Laugier, Frédéric; Pfister, Michael (Eds.) et al Labyrinth and Piano Key Weirs II - PKW 2013 (2013)

A systematic experimental study has been carried out to compare the residual energy at the toe of a stepped spillway of varied length considering a classical ogee-crested weir (OCW) or two different piano ... [more ▼]

A systematic experimental study has been carried out to compare the residual energy at the toe of a stepped spillway of varied length considering a classical ogee-crested weir (OCW) or two different piano key weirs (PKW) at the top of the structure. Four spillway lengths have been considered on a wide range of discharge. An indirect method has been used to compute the residual flow energy at the spillway toe from water depth measurements in a horizontal channel downstream. The results indicate that uniform flow conditions, i.e. flow energy at the spillway toe independent of the spillway length, are reached on significantly shorter spillways downstream of a PKW than downstream of an OCW. However, the uniform flow energy at constant discharge on the spillway is found to vary depending on the weir type. In particular, it is smaller downstream of the OCW than downstream of the PKWs. [less ▲]

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See detailEscouloubre Piano Key weir: prototype versus scale models
Erpicum, Sébastien ULg; Silvestri, Aurélien ULg; Dewals, Benjamin ULg et al

in Erpicum, Sébastien; Laugier, Frédéric; Pfister, Michael (Eds.) et al Labyrinth and Piano Key Weirs II - PKW 2013 (2013)

A 1.77 m high piano key weir in operation on the Escouloubre balance basin enabled the observation of real size flows for discharges ranging from 1.2 to 10 m³/s, corresponding to upstream heads ranging ... [more ▼]

A 1.77 m high piano key weir in operation on the Escouloubre balance basin enabled the observation of real size flows for discharges ranging from 1.2 to 10 m³/s, corresponding to upstream heads ranging from 11 to 48 cm. These observations are depicted and compared to the results gained on three physical models of the weir, built and operated considering a Froude similitude and geometric scale factors of, respectively, 1:7, 1:15 and 1:25. The study highlights the scale effects which may affect piano key weirs scale model studies and provides criteria to limit them. In particular, the results analysis shows that the scale models succeed in representing the flow conditions on the weir when the model upstream head is higher than 60 mm, and succeed in predicting the weir discharge capacity when the model upstream head is higher than 30 mm. [less ▲]

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See detailÉtude de la dissipation d'énergie sur un coursier en marches d'escalier en aval d'un évacuateur de crue de type PKW
Silvestri, Aurélien ULg

Master's dissertation (2012)

The present research follows a previous study led by Erpicum et al. in 20112. The main purpose of this study is to affirm by experiments the theory, which states that in some particular cases, using a ... [more ▼]

The present research follows a previous study led by Erpicum et al. in 20112. The main purpose of this study is to affirm by experiments the theory, which states that in some particular cases, using a piano key weir (PKW) at the top of a stepped spillway instead of a standard ungated spillway with an equal length would result in an increased dissipation of energy. Another way to present this theory is to show that specific geometrical dimensions of the piano key weir can be determined to reach an uniform flow for reduced dimensions of stepped spillways (compared to standard ungated weir). The second goal is to set up analytical methods enabling the evaluation of the energy dissipation on this kind of construction using basic data’s (ex. inclination and geometry of the spillway, geometry of the steps on the spillway, flow,…). In order to reach those objectives, a series of experiments has been executed on a facility at the HECE laboratory. The tests allowed us to acquire different hydraulic parameters that have been used to calculate the energy dissipation on the reduced bench test. It is important to notice that we used an experimental analyzing method for signals. First of all, we have been able to prove the validity of the initial theory using the results of the tests on the facility. Secondly, the analyze and interpretation of the results led us to define criteria’s indicating the apparition of the uniform or non uniform flow depending of the kind of weir used on the spillway. Finally, using the results of the tests we established some analytical formulas for each kind of flow on a free weir and a PKW. Those analytical formulas present a correlation with experiments moreless accurate depending on the interpolation choosen and the set of bench tests realized. [less ▲]

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