Ultrasonic Wind Measurement Array Optimization Design

At present,ultrasonic wind measurement technology is a research hotspot in China and worldwide,and the domestic technology level is not advanced enough.There is still a lot of room for development of measurement technology of high-precision or high-stability,and that in special environments.At present stage,most researches on ultrasonic wind measurement technology focus on the hardware system,while the influence of wind field flow characteristics and algorithm noise is frequently neglected.Therefore,in-depth research is particularly needed in the optimization design of wind measurement arrays.Aiming at the shortcomings of traditional ultrasonic wind measurement arrays,this paper studies two optimization methods for wind measurement arrays: designing an optimizing array based on the improved time difference method and deriving the calculation model of wind speed and direction,using CFD analysis method to perform simulated comparison experiments on the wind measurement array to the wind measurement accuracy of the modified array;optimizing the design of the wind measurement array based on the beam-forming algorithm,deriving the wind measurement algorithm in detail and conducting performance analysis.Illustrating that this method has a good measurement effect under the low signal-to-noise ratio via simulation experiment,and designing a comparison experiment for the flow around the wind measurement array to verify the accuracy and stability of the annular array.Aiming at the problem that the vertical intersecting array is easily affected by the shadow effect and according to the principle of the time difference method,three sets of ultrasonic transducers are placed at 120° with each other,and an improved wind measurement array with three independent wind measurement paths is designed and established along with the model of wind speed calculation.In the process of constructing the CFD analysis framework,the author screened commonly used analysis methods and the finite volume method was selected for analysis,introduced the three control equations of fluid mechanics and the turbulence model,and selected the RNG k-? model for solution computing.The author also used Space Claim to establish wind measurement array and wind tunnel model,conducted FEM through Meshing,changed the wind speed and Reynolds number in the simulated wind tunnel via Fluent,and simulated the performance of the two arrays under different flow regimes.The results of the solution calculation are post-processed through the CFD-POST software,and the velocity distribution cloud map and the wind path velocity curve graph are obtained,and the advantages of the improved array are verified by analyzing the data.Experiment results showed that the modified array can effectively improve the shadow effect.From the perspective of array signal processing algorithm,the author analyzed and discussed the pros and cons of the existing arc-shaped array and proposed a new ultrasonic wind measurement based on the beam-forming algorithm in order to solve the increasingly difficult problem of measuring the ultrasonic propagation time difference in a strong noise environment,and designed the optimized structure of the annular array and derived the flow pattern matrix and related algorithms,and discussed the rationality and reliability of the wind measurement method through performance analysis.The author used Matlab software to perform simulation experiments on the wind measurement algorithm to verify its feasibility and analyze the measurement error under different signal-to-noise ratios,which shows that the method is reliable under complex circumstances.The CFD analysis method is used to conduct comparative experiments on the flow around of the two arrays,thus verified the performance of the annular array under the influence of turbulence,and provide a theoretical basis for the development of a new ultrasonic wind measurement system.