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RE: [PSUBS-MAILIST] depth to psi
The simple multiplicative conversion factor is probably more than adequate for most folks.
But for anyone else thinks that more math is ALWAYS better ;)
http://www.navlab.net/Publications/From_Pressure_to_Depth_-_Estimation_of_underwater_vertical_position.pdf
http://unesdoc.unesco.org/images/0005/000598/059832eb.pdf
Basically, the simple multiplication factor just assumes several things are constant which are not really constant (water density, homogeneity of the water column, atmospheric pressure, flow induced pressure changes, etc.)
You can add as much complexity as you want in order to remove those assumptions. Of course that doesn't even get into sensor calibration....
-andy
ps. Metric IS way easier...10m ~= 1 atm ;)
-----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Jon Wallace
Sent: Sunday, September 11, 2011 8:42 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] depth to psi
The less math, the better. Greg's method should provide enough accuracy for most purposes, but I always tend to use .445 for sea water.
Depth = PSI / .445
PSI = Depth * .445
Jon
On 9/11/2011 2:22 PM, Gregory Cotton wrote:
> Correct; with minor corrections for fresh/salt water (and salinity
> corrections in salt), and temperature.
>
> For basic figuring just figure 0.45 psi per foot of depth.
>
> Greg
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