System and method for measuring spatially resolved velocity and density of air flows simultaneously

A method, comprising:

• scattering an air flow of molecules with a two-dimensional light sheet at a measurement region;
• acquiring one or more first images of scattered light from the measurement region via a first camera coupled to a first filter, wherein the first camera is oriented toward the measurement region from a first angle with respect to a direction of the two-dimensional light sheet;
• acquiring one or more second images of scattered light from the measurement region via a second camera coupled to a second filter, wherein the second camera is oriented toward the measurement region at a second angle with respect to the direction of the two-dimensional light sheet;
• and
• determining a two-dimensional spatial distribution of density and velocity values of the air flow of molecules based on the one or more first images acquired via the first camera and the one or more second images acquired via the second camera,
• wherein the first angle and the second angle are selected such that a Doppler shift used in determining the two-dimensional spatial distribution of density and velocity values of the air flow of molecules at either the first angle or the second angle is zero.

A measurement apparatus, comprising:

• a laser configured to form a two-dimensional light sheet for interrogating an air flow of molecules at a measurement region;
• a first camera disposed on a measurement plane with respect to the laser and oriented toward the measurement region at a first angle with respect to a direction of the two-dimensional light sheet, wherein the first camera is configured to acquire images of scattered light from the measurement region at the first angle;
• and
• a second camera disposed on the measurement plane with respect to the laser and oriented toward the measurement region at a second angle with respect to the direction of the two-dimensional light sheet, wherein the second camera is configured to acquire images of scattered light from the measurement region at the second angle,
• wherein the first angle and the second angle are selected such that the first camera and the second camera are not directly opposing one another about the measurement region, or neither anti-parallel nor parallel to one another about the measurement region, and
• wherein the second angle is selected such that the images acquired via the first camera comprise data associated with a spatial distribution of density and velocity values of the air flow of molecules and the images acquired via the second camera comprise data associated with a spatial distribution of density values and not velocity values of the air flow of molecules.