scholarly journals Removing Wave Bias from Velocity Measurements for Tracer Transport: The Harmonic Analysis Approach

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1138 ◽  
Author(s):  
Sangdon So ◽  
Arnoldo Valle-Levinson ◽  
Jorge Armando Laurel-Castillo ◽  
Junyong Ahn ◽  
Mohammad Al-Khaldi
Keyword(s):  
Harmonic Analysis ◽  
Gravity Wave ◽  
Wave Energy ◽  
Acoustic Doppler Current Profiler ◽  
Surface Gravity ◽  
Tracer Transport ◽  
Velocity Measurements ◽  
Surface Gravity Wave ◽  
Current Profiler ◽  
Adcp Measurements

Estimates of turbulence properties with Acoustic Doppler Current Profiler (ADCP) measurements can be muddled by the influence of wave orbital velocities. Previous methods—Variance Fit, Vertical Adaptive Filtering (VAF), and Cospectra Fit (CF)—have tried to eliminate wave-induced contamination. However, those methods may not perform well in relatively energetic surface gravity wave or internal wave conditions. The Harmonic Analysis (HA) method proposed here uses power spectral density to identify waves and least squares fits to reconstruct the identified wave signals in current velocity measurements. Then, those reconstructed wave signals are eliminated from the original measurements. Datasets from the northeastern Gulf of Mexico and Cape Canaveral, Florida, are used to test this approach and compare it with the VAF method. Reynolds stress estimates from the HA method agree with the VAF method in the lower half of the water column because wave energy decays with depth. The HA method performs better than the VAF method near the surface during pulses of increased surface gravity wave energy.

Non-stationary regimes of surface gravity wave turbulence

JETP Letters ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 459-465 ◽  
Author(s):  
R. Bedard ◽  
S. Lukaschuk ◽  
S. Nazarenko
Keyword(s):  
Gravity Wave ◽  
Surface Gravity ◽  
Wave Turbulence ◽  
Surface Gravity Wave

scholarly journals A Method for Processing Acoustic Doppler Current Profiler Velocity Data from Towed, Undulating Vehicles

2008 ◽  
Vol 25 (9) ◽  
pp. 1710-1716 ◽  
Author(s):  
Jiayi Pan ◽  
David A. Jay
Keyword(s):  
Surface Waters ◽  
High Frequency ◽  
Acoustic Doppler Current Profiler ◽  
Small Time ◽  
Ocean Current ◽  
Near Surface ◽  
Vertical Range ◽  
External Reference ◽  
Current Profiler ◽  
Adcp Measurements

Abstract The utility of the acoustic Doppler current profiler (ADCP) for sampling small time and space scales of coastal environments can be enhanced by mounting a high-frequency (1200 kHz) ADCP on an oscillating towed body. This approach requires both an external reference to convert the measured shears to velocities in the earth coordinates and a method to determine the towed body velocities. During the River Influence on the Shelf Ecosystems (RISE) project cruise, a high-frequency (1200 kHz) and narrowbeam ADCP with mode 12 sampling was mounted on a TRIAXUS oscillating towfish, which steers a 3D path behind the ship. This deployment approach extended the vertical range of the ADCP and allowed it to sample near-surface waters outside the ship’s wake. The measurements from a ship-mounted 1200-kHz narrowbeam ADCP are used as references for TRIAXUS ADCP data, and a method of overlapping bins is employed to recover the entire vertical range of the TRIAXUS ADCP. The TRIAXUS vehicle horizontal velocities are obtained by removing the derived ocean current velocity from the TRIAXUS ADCP measurements. The results show that the method is practical.

scholarly journals Divergence-Free Spatial Velocity Flow Field Interpolator for Improving Measurements from ADCP-Equipped Small Unmanned Underwater Vehicles

2012 ◽  
Vol 29 (3) ◽  
pp. 478-484 ◽  
Author(s):  
Jamie MacMahan ◽  
Ross Vennell ◽  
Rick Beatson ◽  
Jenna Brown ◽  
Ad Reniers
Keyword(s):  
Flow Field ◽  
Signal To Noise Ratio ◽  
Acoustic Doppler Current Profiler ◽  
Unmanned Underwater Vehicles ◽  
Velocity Magnitude ◽  
Velocity Flow ◽  
Current Profiler ◽  
Adcp Measurements ◽  
Measured Flow ◽  
Divergence Free

Abstract Applying a two-dimensional (2D) divergence-free (DF) interpolation to a one-person deployable unmanned underwater vehicle’s (UUV) noisy moving-vessel acoustic Doppler current profiler (MV-ADCP) measurements improves the results and increases the utility of the UUV in tidal environments. For a 3.5-h MV-ACDP simulation that spatially and temporally varies with the M2 tide, the 2D DF-estimated velocity magnitude and orientation improves by approximately 85%. Next the 2D DF method was applied to velocity data obtained from two UUVs that repeatedly performed seven 1-h survey tracks in Bear Cut Inlet, Miami, Florida. The DF method provides a more realistic and consistent representation of the ADCP measured flow field, improving magnitude and orientation estimates by approximately 25%. The improvement increases for lower flow velocities, when the ADCP measurements have low environmental signal-to-noise ratio. However, near slack tide when flow reversal occurs, the DF estimates are invalid because the flows are not steady state within the survey circuit.

Observations of surface-gravity-wave scattering and dissipation by an isolated shoal related to a cuspate foreland

2019 ◽  
Vol 173 ◽  
pp. 43-55 ◽  
Author(s):  
Juan F. Paniagua-Arroyave ◽  
Peter N. Adams ◽  
Sabrina M. Parra ◽  
Arnoldo Valle-Levinson
Keyword(s):  
Gravity Wave ◽  
Wave Scattering ◽  
Surface Gravity ◽  
Surface Gravity Wave
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