US Patent 9567056 Devices, systems and methods for passive control of flow

Systems, devices and methods are disclosed for controlling the flow of a fluid over the window of an optical instrument housing in a freestream flow field. For example, the flow upstream of the housing may be split to create a flow region over the window that is conducive to successful operation of the instrument. The flow region may be maintained for various rotations of the housing about yaw, pitch, and roll axes. The disclosed features in some embodiments induce flow regions with reduced spatial and temporal density gradients of the flow over the window.