Convert the shear probe data: Difference between revisions
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<math> s=\frac{N_s}{2\sqrt2SU^2G\gamma} </math> | <math> s=\frac{N_s}{2\sqrt2SU^2G\gamma} </math> | ||
where <math>s</math> is the shear signal in physical units of <math>\mathrm{s}^{-1}</math> , <math>N_s</math> are the raw numeric samples (the output of an analog-to-digital converter), <math>S</math> is the calibrated sensitivity of the shear-probe in units of <math>\mathrm{V/(m | where <math>s</math> is the shear signal in physical units of <math>\mathrm{s}^{-1}</math> , <math>N_s</math> are the raw numeric samples (the output of an analog-to-digital converter), <math>S</math> is the calibrated sensitivity of the shear-probe in units of <math>\mathrm{V/(m\,s^{-1})^2}</math>, <math>U</math> is the speed of profiling in <math>\mathrm{m\,s^{-1}}</math>, <math>G</math> is the gain of the electronics of the shear probe in units of <math>\mathrm{s}</math>, and <math>\gamma</math> is the gain of the analog-to-digital converter used to create the samples in units of <math>\mathrm{counts\, V^{-1}}</math>. | ||
The sensitivity of the shear probe to shear is proportional to the square of the speed of profiling. | The sensitivity of the shear probe to shear is proportional to the square of the speed of profiling. | ||
Thus, one should set a minimum speed for the conversion of the shear-probe data into physical units. Otherwise, the conversion may produce enormously large and quite unrealistic values. | Thus, one should set a minimum speed for the conversion of the shear-probe data into physical units. Otherwise, the conversion may produce enormously large and quite unrealistic values. | ||
Realistic minimum speeds for the conversion into physical units are <math>0.05</math> to <math>0.1\, \mathrm{m\,s^{-1}}</math> because the shear-probe signal is likely to be dominated by electronic noise and the angle of attack will be large (<math> >20^{\circ}</math>) even for low levels of dissipation. | Realistic minimum speeds for the conversion into physical units are <math>0.05</math> to <math>0.1\, \mathrm{m\,s^{-1}}</math> because the shear-probe signal is likely to be dominated by electronic noise and the angle of attack will be large (<math> >20^{\circ}</math>) even for low levels of dissipation. |
Revision as of 18:38, 13 July 2021
copy&paste from V1 docx
Convert the shear-probe data samples into physical units using the standard equation,
where
The sensitivity of the shear probe to shear is proportional to the square of the speed of profiling.
Thus, one should set a minimum speed for the conversion of the shear-probe data into physical units. Otherwise, the conversion may produce enormously large and quite unrealistic values.
Realistic minimum speeds for the conversion into physical units are