Single Beam Optical Cross-Flow Sensor Using Fourier Transform
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Solution Overview
Problem
Current remote sensing methods for cross-flow orientation of fluids over extended ranges, such as in meteorology and wind farm surveys, are limited by the inability of single large-aperture scintillometers to determine flow direction, relying instead on dual beam systems that are more complex and costly.
Innovation Solution
A system utilizing a single laser beam's wander, measured in two orthogonal directions through Fourier transformation, allows for the determination of cross-flow orientation using a position sensitive detector, simplifying the setup and enabling remote sensing of fluid flow orientation over extended ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single large-aperture scintillometer is used, then the measurement range is extended and setup is simplified, but the ability to determine flow direction is lost
Solution Approach 1:
The patent measures beam wander in two orthogonal directions (x and y dimensions) using a single detector, transforming a one-dimensional measurement into a two-dimensional measurement. This dimensional expansion enables flow direction determination from a single beam, resolving the contradiction between simplified setup and loss of directional information.
2Loss of information
If dual beam scintillometer systems are used, then flow direction can be determined, but device complexity and cost increase
Solution Approach 1:
The patent merges the functionality of two separate beam measurements into a single beam measurement by detecting wander in two orthogonal directions simultaneously. This consolidation maintains flow direction determination capability while reducing system complexity and cost associated with dual beam systems.
Solution Approach 2:
The single position-sensitive detector serves multiple functions: it measures beam wander in both x and y directions, enabling simultaneous determination of flow speed and flow direction from a single beam, thus achieving multi-functionality with a single component.
3Loss of information
If beam wander is measured in two orthogonal directions, then flow orientation can be determined, but measurement precision requirements increase
Solution Approach 1:
The patent replaces complex mechanical dual-beam measurement systems with an optical/electronic single-beam position-sensitive detector system. The PSD electronically resolves beam position in two orthogonal directions, reducing mechanical complexity while maintaining measurement precision through electronic detection methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate and efficient remote sensing of cross-flow orientation in turbulent fluids, reducing complexity and cost compared to dual beam systems, while providing comprehensive data for wind direction and speed.
Implementation Method 1
Position sensitive detectors (PSD) can use, for example, photodiode surface resistance to provide position data (X or Y coordinate data)
Implementation Method 2
The wind direction of the atmosphere is routinely monitored by remote sensing techniques such as Light Detection and Ranging (LIDAR) and Sonic Detection and Ranging (SODAR). The measurement principles usually employed are the Doppler shift in applications where the flow is in the direction of the detecting beam
Data Source
AI summary
System and method for remotely sensing the cross-flow orientation of a fluid (including a gaseous fluid) over an extended range. A Fourier transform of beam wander of a single beam can be used to determine the orientation of the flow field. Many applications depend upon accurate flow orientation data to provide correct information such as, for example, citing of turbines on wind farms and atmospheric/ocean weather prediction.