The Bessel functions ber and bei used in and have as an argument. Further

Define the complex mean velocity through the tube as

The equivalent resistance of the tube as and the normalized resistance as . Values of as a function of are given in Table 2. The reciprocal of the normalized resistance is a measure of the attenuation factor.

Table 2: Attenuation Factor for a Pitot Probe as a Function of the Dimensionless Frequency