Spillway Crest Geometry to Prevent Water Layer Detachment

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Solution Overview

Problem

Existing spillway geometries fail to optimize flow rate without water column detachment, leading to structural instability and damage due to air currents and water table fluctuations.

Innovation Solution

A spillway structure with an upper surface featuring alternating bumps and hollows, constructed through a variable homothety transformation of a basic profile, which increases the permissible flow rate without separation by shifting the separation point upwards in the head-discharge relationship.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If standard profiled weir geometry is used, then the spillway operates optimally at design flow rate, but the permissible flow rate without water column detachment is limited

Engineering Contradiction:
Improvepermissible flow rate without detachmentVSAvoidwater column stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention introduces localized geometric modifications (bumps and hollows) at specific locations on the weir crest rather than changing the entire profile. These localized features create controlled air injection zones that prevent water column detachment while maintaining optimal flow characteristics at the design point.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses air as an intermediary substance by introducing air bubbles through the bumps and hollows on the weir crest. This air layer acts as a mediator between the water flow and the weir surface, preventing direct detachment and stabilizing the water column at higher flow rates.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If known spillway geometries are used, then aeration of the overflowing aquifer is achieved, but the throughput performance is insufficient

Engineering Contradiction:
Improvethroughput flow rateVSAvoidgeometric complexity of spillway surface
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The weir crest surface is segmented into multiple alternating bumps and hollows rather than using a single continuous profile. This segmentation creates multiple discrete air injection points along the flow path, enabling effective aeration and detachment prevention without requiring excessive overall geometric complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional weir profile to a three-dimensional surface by adding bumps and hollows that extend into the flow path. This dimensional addition creates new flow paths and air injection zones that enhance throughput capacity without proportionally increasing manufacturing complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The new geometry enhances hydraulic performance by increasing the permissible flow rate by at least 20% to 100% without water layer detachment, improving flow adhesion and reducing structural instability.

Implementation Method 1

the invention increases the permissible flow rate without detachment compared to the structures described in the documents mentioned above. The invention also improves the flow's adhesion to the surface

Methodology Applied
Scientific EffectFlow separation: Flow Separation

Implementation Method 2

The invention makes it possible to increase the maximum permissible discharge over the upper weir surface without observing separation of the overflowing water layer, that is, without air being forced between the overflowing water layer and the upper weir surface

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4339374B1Pouring structure, hydraulic dam provided with same
Publication Date: 2026.01.21 ELECTRICITE DE FRANCE
  • EP4339374B1 patent drawingFigure 1A
  • EP4339374B1 patent drawingFigure 1B
  • EP4339374B1 patent drawingFigure 2

AI summary

The invention relates to a spillway structure (1), comprising an upstream face (2), which obstructs the flow of water, and an upper surface (4) forming a weir crest. The invention is characterized in that the upper weir crest surface (4) has at least one bump (41) and at least one depression (42) in at least one plane (Pyz) of width, parallel to the transverse direction (Oy) and the vertical direction (Oz), and/or in at least one horizontal plane (Pxy), parallel to the horizontal direction (Ox) and the transverse direction (Oy).