Eel Diversion Device with Flow Shadow Element

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Solution Overview

Problem

Current diversion systems for eels at hydraulic structures are ineffective due to difficulty in locating entry openings against strong currents, potential damage from high pressure differences, and clogging issues, which hinder eels' safe passage around hydroelectric power plants.

Innovation Solution

A diversion system with a collecting line in the upstream water featuring a flow shadow-generating element at the bottom of the river, creating a flow shadow area where the openings are located, and a bypass line that connects to a gutter system to guide eels safely past the hydraulic structure, with a pumping and flushing system for maintenance and cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the collecting line openings are positioned in the upstream water against the current, then eels can be diverted, but eels cannot locate the openings due to the strong current masking the lure current

Engineering Contradiction:

Improvediversion effectivenessVSAvoidopening detectability

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

A flow shadow-generating element is introduced as an intermediary between the main current and the collecting line openings. This element creates a flow shadow zone where the strong main current is blocked, allowing the weaker lure current from the openings to become detectable by eels without being masked by the dominant flow direction

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The flow shadow creates a localized zone with different flow characteristics - a region where the current strength and direction differ from the main flow. This local modification of flow quality allows eels to detect openings in an area that is otherwise dominated by the strong upstream current

Inventive Principle:

Principle #3Local quality

2Productivity

If the collecting line directly connects upper water to lower water, then diversion is achieved, but strong pressure differences cause high inflow velocities that damage eels

Engineering Contradiction:

Improvediversion efficiencyVSAvoideel damage from high velocity

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The direct connection between upper and lower water is segmented into multiple sections: an upper collection section, a vertical descent section, and a lower discharge section. This segmentation allows the pressure difference to be distributed across multiple transitions rather than creating a single high-velocity drop, reducing harmful effects on eels

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bypass line is designed with gradual transitions and appropriate dimensions to cushion the pressure change before eels enter the high-pressure zone. The system prepares a gentler entry path that reduces the shock and velocity exposure for eels before they complete the descent

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If the collecting line is positioned at the bottom of the river, then eels can find protection, but the openings become hidden from eels fleeing the obstacle

Engineering Contradiction:

Improveeel access to refugeVSAvoidopening visibility

Core Design Contradiction:

Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The flow shadow-generating element acts as an intermediary that creates a visible flow pattern in the bottom water zone. This mediator makes the hidden openings detectable by creating a local flow shadow that eels can sense, allowing them to locate openings while maintaining their natural bottom-seeking behavior

Inventive Principle:

Principle #24Intermediary (Mediator)

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 system makes it easier for eels to find and enter the diversion by creating a perceivable suction effect within the flow shadow, reduces pressure-related damage, and prevents clogging through effective flushing, ensuring eels can safely bypass hydraulic structures.

Implementation Method 1

a flow shadow-generating element ( 40 ) arranged upstream of the opening or openings of the manifold ( 30 )

Methodology Applied

Scientific EffectFlow shadow: Shadow

Implementation Method 2

creating a perceivable suction effect within the flow shadow

Methodology Applied

Scientific EffectSuction effect: Suction

Data Source

PatentEP2666910B1Device for the descent of eels at hydraulic structures

Publication Date: 2016.01.27 UNIVERSITY OF KASSEL

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AI summary

A device (10) for the descent of eels at hydraulic structures comprises a fish protection system (20) arranged in the upstream water (O) and a diversion system (50) for bypassing the hydraulic structure. The diversion system includes at least one collecting pipe (30) with at least one opening (31) in the upstream water (O) to receive the eels. This opening is located in the region of the bed (B) of the flowing water (F) in the direction of flow (S). To ensure that the eels actually find the bypass system, the invention provides for a flow shadow-generating element (40) upstream of the openings (31) of the collecting pipe (30). To gently equalize pressure differences between the upstream water (O) and downstream water (U) for the eels, the invention provides a bypass pipe (51) with a pumping and flushing system (70) for the diversion system (50).