vertical noise side looking vectrino

I am collecting data using a side-looking vectrino probe and have noticed that the vertical velocity component tends to be much noisier than the X and Y components.  I've tried seeding the water but this doesn't improve it much, and the X and Y components look fine with little noise.  I've also looked at the probe check and do not readily notice any problems with the signal.  I read in a previous post that the vertical direction with the side looking probe tends to be noisier than normal.  Why is this, and is there a way to reduce the noise?  Are others having similar problems?

Thank you!

Hi Craig,

Tahink of the side looking probe as essentially the standard probe turned on its side to understand why there is higher noise in the vertical component. In a standard head, the vertical component is closely aligned with the bi-static axis resulting in lower noise compared to the horizontal and vertical components. In the side looking head, it's the Y component that is most closely aligned with the bi-static axis. The X component will have a similar noise floor to the vertical, but with a higher streamwise velocity the noise is a much smaller percentage of the velocity than for the vertical. This is unfortunately a consequence of the head geometry so I'm sure other users have struggled with it.

My best advice is to select the lowest velocity range you can for your flow conditions and if vertical velocities are important to measure with minimal noise, consider using either a standard head if flow conditions permit or rotating the side looking head so Y is measuring the vertical component is you don't have access to a standard head.

P.J.