A New Cross-Platform Instrument for Microstructure Turbulence Measurements

Nie, Yunli; Yang, Hua; Song, Dalei; Huang, Yan; Liu, Xiuyan; Hui, Xianghua

doi:10.3390/jmse9101051

Cited by 3 publications

(7 citation statements)

References 28 publications

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“…This layout allows sensors to be located away from the aft propulsion system, improving data sampling accuracy while preserving the AUV's low drag profile. The CPMTM is designed by the Ocean University of China [21], as shown in Figure 2. It is housed in a pressure case of 0.08 m diameter and is approximately 0.6 m long.…”

Section: Turbulence Auvmentioning

confidence: 99%

“…To determine the optimal layout distance, the CFD method was used to estimate the hydrodynamic properties of the turbulence AUV in various angles of attack and speeds. The CPMTM is designed by the Ocean University of China [21], as shown in Figure 2. It is housed in a pressure case of 0.08 m diameter and is approximately 0.6 m long.…”

Section: The Layout Optimization Of Cpmtmmentioning

confidence: 99%

“…The shear probe is located at the X distance from the nose of the AUV, outside the region of flow deformation (Figure 1a), and the optimal layout distance will be described in Section 3. The CPMTM is designed by the Ocean University of China [21], as shown in Figure 2. It is housed in a pressure case of 0.08 m diameter and is approximately 0.6 m long.…”

Section: The Layout Optimization Of Cpmtmmentioning

confidence: 99%

“…Both shear spectra agree well with the Nasmyth spectrum in the range of 2∼36 cpm. With the assumption of isotropic turbulence [5,19], the dissipation rate of turbulent kinetic energy (ε) is calculated by integrating the shear spectra as [21,25]…”

Section: Shear Data Analysismentioning

confidence: 99%

“…where the lower integration limit 𝑘 the upper limit of integration 𝑘 represent the wavenumber interval with good agreement between shear spectra and Nasmyth spectrum. The dissipation rates based on the measured shear spectra (Figure 15a) are ε1 = 8.5 × With the assumption of isotropic turbulence [5,19], the dissipation rate of turbulent kinetic energy (ε) is calculated by integrating the shear spectra as [21,25]…”

Section: Shear Data Analysismentioning

confidence: 99%

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Design and Motion Performance Analysis of Turbulent AUV Measuring Platform

Nie

Song

Wang

et al. 2022

Sensors

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The use of a multi-functional autonomous underwater vehicle (AUV) as a platform for making turbulence measurements in the ocean is developed. The layout optimization of the turbulence package and platform motion performance are limitation problems in turbulent AUV design. In this study, the computational fluid dynamics (CFD) method has been used to determine the optimized layout position and distance of the shear probe integrated into an AUV. When placed 0.8 D ahead of the AUV nose along the axis, the shear probe is not influenced by flow distortion and can contact the water body first. To analyze the motion of the turbulence AUV, the dynamic model of turbulence AUV for planar flight is obtained. Then, the mathematical equations of speed and angle of attack under steady-state motion have also been obtained. By calculating the hydrodynamic coefficients of the turbulence AUV and given system parameters, the simulation analysis has been conducted. The simulation results demonstrated that the speed of turbulent AUV is 0.5–1 m/s, and the maximum angle of attack is less than 6.5°, which meets the observation requirements of the shear probe. In addition, turbulence AUV conducted a series of sea-trials in the northern South China Sea to illustrate the validity of the design and measurement. Two continuous profiles (1000 m) with a horizontal distance of 10 km were completed, and numerous high-quality spatiotemporal turbulence data were obtained. These profiles demonstrate the superior flight performance of turbulence AUV. Analysis shows that the measured data are of high quality, with the shear spectra being in very good agreement with the Nasmyth spectrum. Dissipation rates are consistent with background shear. When shear velocity is weak, the measurement of dissipation rate is 10−10 W Kg−1. All indications are that the turbulence AUV is suitable for long-term, contiguous ocean microstructure measurements, which will provide data needed to understand the temporal and spatial variability of the turbulent processes in the oceans.

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Section: Turbulence Auvmentioning

confidence: 99%

Section: The Layout Optimization Of Cpmtmmentioning

confidence: 99%

Section: The Layout Optimization Of Cpmtmmentioning

confidence: 99%

Section: Shear Data Analysismentioning

confidence: 99%

Section: Shear Data Analysismentioning

confidence: 99%

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Design and Motion Performance Analysis of Turbulent AUV Measuring Platform

Nie

Song

Wang

et al. 2022

Sensors

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Automatic tracking method for submarine cables and pipelines of AUV based on side scan sonar

Feng

Huang

et al. 2023

Ocean Engineering

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Microstructure Turbulence Measurement in the Northern South China Sea from a Long-Range Hybrid AUV

Nie

Luan

Huang

et al. 2023

Sensors

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This study describes the development of a long-range hybrid autonomous underwater vehicle (AUV) for ocean turbulence measurement. It is a unique instrument, combining the characteristics of the conventional AUV and the buoyancy-driven glider, with a variety of flexible motion modes, such as cruise mode, glider mode, drift mode, and combination of multiple motion modes. The hybrid AUV was used for continuous turbulence measurement in the continental slope of the northern South China Sea in 2020. A total of ten continuous profiles were completed covering a horizontal span of 25 Km and a depth of 200 m. The hybrid AUV was operated in the combined glider and cruise mode. The hybrid AUV’s flight performance was stable and satisfied the requirement for turbulence observation. The measured velocity shears from both probes were in good agreement, and the noise-reduced shear spectra were in excellent agreement with the Nasmyth spectrum. The water column in the study area was highly stratified, with a thick thermocline. The dissipation rate (ε) varied from 1.41 × 10−10 to 4.18 × 10−7 W·kg−1. In the surface mixed layer, high values of ε (10−9∼10−8 W·kg−1) were observed toward the water surface. In the thermocline, ε was 10−9.5∼10−9 W·kg−1, which was smaller than the level of the surface mixed layer. This result was mainly because of the strong “barrier”-like thermocline, which damped the transmission of wind and heat energy from the surface mixed layer to the deep layer. Overall, this study demonstrates the utility of hybrid AUVs for collecting oceanic turbulence measurements. They are a powerful addition to traditional turbulence instruments, as they make it possible to survey large areas to obtain high-quality and high-resolution data in both vertical and horizontal directions over long durations.

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A New Cross-Platform Instrument for Microstructure Turbulence Measurements

Cited by 3 publications

References 28 publications

Design and Motion Performance Analysis of Turbulent AUV Measuring Platform

Design and Motion Performance Analysis of Turbulent AUV Measuring Platform

Automatic tracking method for submarine cables and pipelines of AUV based on side scan sonar

Microstructure Turbulence Measurement in the Northern South China Sea from a Long-Range Hybrid AUV

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