US 12,411,152 B2
Method and system for determining flow properties of a fluid flowing along a surface
Alois Friedberger, Hamburg (DE); Bruno Stefes, Hamburg (DE); Dominik Berndt, Regensburg (DE); and Rupert Schreiner, Regensburg (DE)
Assigned to Airbus Operations GmbH, Hamburg (DE); Airbus SAS, Blagnac (FR); and Ostbayerische Technische Hochschule, Regensburg (DE)
Filed by Airbus Operations GmbH, Hamburg (DE); Airbus SAS, Blagnac (FR); and Ostbayerische Technische Hochschule Regensburg, Regensburg (DE)
Filed on Mar. 23, 2023, as Appl. No. 18/188,688.
Claims priority of application No. 22164393 (EP), filed on Mar. 25, 2022.
Prior Publication US 2023/0305035 A1, Sep. 28, 2023
Int. Cl. G01P 5/12 (2006.01)
CPC G01P 5/12 (2013.01) 17 Claims
OG exemplary drawing
 
1. A method for determining flow properties of a fluid flowing along a surface, the method comprising:
modulating a current through a heating element of a thermal flow sensor located on a surface with at least one modulation frequency, thereby emitting a thermal wave into the fluid flowing along the surface having a penetration depth inversely proportional to the at least one modulation frequency;
measuring an amplitude of a voltage across the heating element at a third harmonic of the at least one modulation frequency, the voltage depending on a thermal conductivity and a volumetric heat capacity of the fluid flowing along the surface;
determining a flow velocity at the penetration depth from an attenuation value of the measured amplitude of the voltage; and
estimating whether a flow at the penetration depth is laminar or turbulent based on the determined flow velocity.