CFD-Guided Shadowing-Aware Acoustic Path Selection for Accurate Wind Estimation in Ultrasonic Anemometers

Area of Science:

• Fluid dynamics
• Acoustics
• Meteorological instrumentation

Background:

• Ultrasonic anemometers offer fast, high-resolution wind measurement but suffer from transducer shadowing, causing errors in time-of-flight (TOF) measurements.
• Existing studies on transducer shadowing are limited to low wind speeds and lack mitigation strategies.

Purpose of the Study:

• To analyze wake-induced velocity deficits and their impact on TOF measurements in ultrasonic anemometers.
• To propose and validate a novel method for mitigating shadowing-induced bias in wind measurements.

Main Methods:

• A coupled computational fluid dynamics (CFD) and acoustic propagation framework was developed.
• Simulations covered a wide range of wind speeds (5-75 m/s) and all directions (360°).
• A shadowing-aware acoustic path selection method was proposed and tested.

Main Results:

• Shadowing distortions are direction-dependent, peaking in specific angular sectors with significant velocity deficits.
• The proposed shadowing-aware method reduced average velocity RMSE to 0.349 m/s and directional RMSE to 1.14°.
• Improvements were more than an order of magnitude compared to shadow-unaware methods.

Conclusions:

• A physically grounded, simulation-based framework for shadowing-aware wind measurement using ultrasonic anemometers has been established.
• The proposed method effectively mitigates shadowing-induced bias, enhancing wind measurement accuracy.
• This research paves the way for more reliable ultrasonic anemometry in diverse conditions.