CHEN Biao,LIU Tao.Analysis of Flow Characteristics of Flaring Pier Combined with Underflow Energy Dissipation Based on Three-Dimensional Numerical Simulation[J].PEARL RIVER,2026,47(06):82-91.
CHEN Biao,LIU Tao.Analysis of Flow Characteristics of Flaring Pier Combined with Underflow Energy Dissipation Based on Three-Dimensional Numerical Simulation[J].PEARL RIVER,2026,47(06):82-91.DOI: 10.3969/j.issn.1001-9235.2026.06.008.
Analysis of Flow Characteristics of Flaring Pier Combined with Underflow Energy Dissipation Based on Three-Dimensional Numerical Simulation
Ensuring safe flood discharge and efficient energy dissipation under high head and large unit discharge is a critical challenge in high dam engineering. The combination of flaring piers and underflow energy dissipation provides an effective solution. To optimize the geometric design of flaring piers
this study takes the Xuanwei Reservoir project as a case study. A three-dimensional hydrodynamic model was developed using the RNG k-ε turbulence model and the Volume of Fluid (VOF) method
and validated against physical experiments. The validation results confirm that the RNG k-ε model can effectively reproduce the complex flow characteristics associated with flaring piers combined with underflow energy dissipation. The effects of the contraction ratio (
λ
) and the horizontal projection length of the contraction section (
l
) on the flow field
velocity
pressure distribution
and energy dissipation efficiency in the stilling basin were systematically analyzed. The results indicate that the contraction ratio is the dominant parameter controlling energy dissipation performance. A weakly constrained configuration with a large contraction ratio (
λ
= 0.615
l
= 6 m) leads to excessively high jet velocities downstream of the pier
posing a risk to the bottom slab. In contrast
a strongly constrained configuration with a small contraction ratio (
λ
= 0.385
l
= 6 m) tends to produce a concentrated high-velocity jet
resulting in elevated velocities at the end sill and insufficient energy dissipation. Based on a comparative analysis of multiple configurations
an optimal scheme with
λ
= 0.462 and
l
= 7 m was identified. Under this scheme
velocities along the stilling basin and at the end sill are minimized
the flow forms a thick w
ater tongue with a low exit angle and a smooth transition
and the pressure distribution is improved. The energy dissipation efficiency reaches 71.52%
achieving a favorable balance between energy dissipation performance and structural safety.
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