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Displacement piston wavemakers

Piston-style wavemaker

Displacement piston wavemaker

The Edinburgh Designs displacement piston wavemaker is a complete absorbing random piston wavemaker that includes the paddle, drive motor, control electronics and power supply. The unit uses a displacement technique that allows perfect flat front piston action without using seals. The unit is supplied ready to fit to the end of an existing narrow flume.

The main advantages of this type of wavemaker compared to others are:

animated piston movemnent

Edinburgh Designs Displacement Piston in Motion



6m wide piston tank

A 6m wide piston tank

7.5m wide piston tank with waves

A 7.5m wide piston tank with waves

A 7.5m wide piston tank

A 7.5m wide piston tank

Paddle construction

The structure is light and corrosion resistant.The support structure holds the sector-carrier in a modular unit. The upper section of the structure has the mountings for the motor, air springs, operating linkages and the main carrier hinge.The largest force on the sector-carrier is the buoyancy, followed by the wavemaking forces and the inertial forces due to acceleration. Drive is by brushless AC servo-motor driving a kevlar belt fixed to the sector body.

Absorption

detailed diagram of piston

Diagram of piston in action

Traditionally wavemakers work with a position feedback control system to create waves. This has the disadvantage that the swept volume of the paddle is dependant on the water level in front of the paddle. So the wave height generated is dependant on many factors including the size of reflected waves from models or poor beaches. The Edinburgh Designs wavemaker measures the incoming wave and corrects the paddle motion to absorb it. The resultant wave field is totally predictable even with highly reflective models.

Dimensions

Variable piston paddle

0.8m wide variable piston paddle

piston paddle creating shallow waves

shallow water waves

Edinburgh designs has built many different sized single wavemakers from 300 to 3500mm wide for water depths of 100 to 1000mm. They can be built to upgrade existing wave tanks so fitting the customer's exact requirements. The size of the wavemaker is illustrated by the relative size of the man undertaking routine maintenance in the left-hand photo of the three at the top of this page.

Tank Layout

It is possible to position the paddle assembly anywhere in a tank. The sector-carrier creates no back wave so requires no back sump The absorbing wavemaker creates high quality waves that are stable within a distance of three water depths from the paddle face. Valuable research can be conducted in laboratories that are too short for a traditional tank. The paddles can be placed opposing each other at either end of a tank to form an active beach or side by side to control crosswaves. Multiple paddles are controlled by a single computer that can be placed up to 50m from the wavemaker.

Harsh Environments

This wavemaker is specifically designed for use in dirty water with suspended particles. It accepts variable water depth and forced currents. The wetted surfaces are non corrosive and maintenance free. The drive is robust with no cooling problems in hot climates.