Next Article in Journal
The Suitability of Snow and Meteorological Conditions of South-Central Slovakia for Ski Slope Operation at Low Elevation—A Case Study of the Košútka Ski Centre
Next Article in Special Issue
Vulnerability Analysis of the Venetian Littoral and Adopted Mitigation Strategy
Previous Article in Journal
Analyzing the Effect of Soil Hydraulic Conductivity Anisotropy on Slope Stability Using a Coupled Hydromechanical Framework
Previous Article in Special Issue
Simulating Future Flows and Salinity Intrusion Using Combined One- and Two-Dimensional Hydrodynamic Modelling—The Case of Hau River, Vietnamese Mekong Delta
Article Menu
Issue 7 (July) cover image

Export Article

Open AccessTechnical Note
Water 2018, 10(7), 906;

Applying a New Force–Velocity Synchronizing Algorithm to Derive Drag Coefficients of Rigid Vegetation in Oscillatory Flows

1,3,* , 3,5,* and 3,5
School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China
State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China
Guangdong Province Engineering Research Center for Coasts, Islands and Reefs, Guangzhou 510275, China
Guangdong Research Institute of Water Resources and Hydropower, Guangzhou 510630, China
School of Marine Engineering and Technology, Sun Yat-sen University, Guangzhou 510275, China
Authors to whom correspondence should be addressed.
Received: 24 May 2018 / Revised: 5 July 2018 / Accepted: 6 July 2018 / Published: 9 July 2018
Full-Text   |   PDF [2749 KB, uploaded 18 July 2018]   |  


Coastal vegetation is effective in dissipating incident wave energy during storm conditions, which offers valuable protection to coastal communities. Determining vegetation drag coefficient (CD) is of great importance to the quantification of vegetation-induced wave dissipation. Recently, a direct measuring approach has been developed to derive vegetation drag coefficient more accurately compared to the conventional calibration approach. However, as this approach requires perfectly in-phase force and velocity signals, there are two difficulties associated with it. The first difficulty is the availability of a suitable force sensor to compose synchronized force–velocity measuring systems. The second difficulty is related to realigning the obtained timeseries of force and velocity data. This technical note develops a new synchronized force–velocity measuring system by using standard force sensors and an acoustic doppler velocimeter (ADV). This system is applied together with an automatic realignment algorithm to ensure in-phase data for CD deviation. The algorithm reduces the phase shift between force–velocity signals from ca. 0.26 s to 0.003 s. Both time-varying and period-averaged CD can be obtained using this method. The derived CD can be used to accurately reproduce the measured maximum total acting force on vegetation (R2 = 0.759), which shows the reliability of the automatic alignment algorithm. The newly-developed synchronized force–velocity measuring system and alignment algorithm are expected to be useful in future experiments on vegetation–wave interactions with various hydrodynamic and vegetation settings. View Full-Text
Keywords: drag coefficients; oscillatory flows; force sensors; synchronization; automatic alignment drag coefficients; oscillatory flows; force sensors; synchronization; automatic alignment

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Yao, P.; Chen, H.; Huang, B.; Tan, C.; Hu, Z.; Ren, L.; Yang, Q. Applying a New Force–Velocity Synchronizing Algorithm to Derive Drag Coefficients of Rigid Vegetation in Oscillatory Flows. Water 2018, 10, 906.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Water EISSN 2073-4441 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top