Measuring Ocean Waves for Wave Energy Projects

[simpsonocean]

Halo everyone. I am new to here!

I am working with a project of ocean wave energy.
I would like have a device that can measure the wave length, pitch those wave parameter when I testing my wave energy device.

Anyone have a clue what kind of device can complete my task?

 

[Baluncore]

How deep is the water where you doing your tests?
How big might the waves be?
How accurate do you need the measurements to be?

I would consider a bottom mounted, up-looking, sonar depth sounder that generates a continuous signal that can be sent to shore along the power cable. By logging that data during the experiment you will have data for an amplitude and wavelength analysis by using an FFT. It will resolve several different wave sources with different wavelengths. If you had doppler you could also measure the circulation velocity of the wave movement.

 

[simpsonocean]

The location should be about 150m away from coast.
-It will about 5-10m deep.
I won't be mega wave in pacific ocean..lol ..
-It should be up to 2m.
-The accuracy is around +-10cm

 

[Bobbywhy]

simpsonocean, Welcome to Physics Forums!

This Wiki page gives a good introduction to the subject and useful information plus references:
http://en.wikipedia.org/wiki/Wave_height

See this from the United States Army Corps of Engineers' Coastal and Hydraulics Laboratory, the Coastal Engineering Manual (CEM) ,Part II, Chapter 1:
http://140.194.76.129/publications/eng-manuals/EM_1110-2-1100_vol/PartII/Part_II-Chap_1.pdf

Here are two paragraphs from the University of California, San Diego that describe types of sensors:
“There are two main types of sensors used to measure sea surface elevation, pressure sensors and buoys. Pressure sensors are mounted at a fixed position underwater, and they measure the height of the water column that passes above them. As wave crests pass by, the height of the water column increases; when troughs approach, the water column height falls. By deducting the depth of the sensor from the water column heights, a record of sea surface elevations can be generated.”

“Buoys ride atop the surface of the ocean. Equipped with accelerometers to record their own movements, buoys rise with the wave crests and fall with the troughs. Since buoys are always floating on the sea surface, by recording their own movements they are in fact recording the movements of the sea surface. Readings from the accelerometers inside the buoys can be used to calculate the buoys' vertical displacements; these values are also a record of sea surface elevation.”
http://cdip.ucsd.edu/?sub=index&nav=documents&xitem=waves

Wave height measurement techniques from Texas A&M University:
http://oceanworld.tamu.edu/resources/ocng_textbook/chapter16/chapter16_06.htm

Here are four manufacturers that sell wave sensors:
http://www.oconnerengineering.com/Marine/wave_height.htm
http://www.nickbelsondesign.co.uk/wave_height_sensors.HTM
http://www.oceanor.com/systems/seawatch/buoys-and-sensor/
http://www.falmouth.com/sensors/tidewavemeters.html

A do-it-yourself wave height sensor project using a tantalum wire: http://journals.ametsoc.org/doi/pdf/10.1175/1520-0426(1995)012<0190:ANWHS>2.0.CO;2

There are also capacitive sensors. You may use Google search to find details about them.