A fluid property measurement system for measuring free stream particulates includes a fluid movement device positioned within a fluid container which is configured to cause fluid flow within the fluid container along a fluid flow path when a fluid is present. A constricted region along the fluid flow path generates a region of concentrated streamlined flow within the constricted region and mixing of the fluid outside of the constricted region. A property measuring device is positioned with respect to the constricted region to measure fluid properties in the region of streamlined flow.