Scope 



The following measurements and analyses are described in this chapter. 

 Measurements. 



a. Time series of profiles of suspended sediment concentration by acous- 

 tic concentration profiler (ACP) with 4-Hz temporal and 1.5-cm 

 spatial resolutions. 



b. Time series of suspended sediment concentration at approximately 



9 and 56 cm above the bed by optical backscatterance sensors (OBS) 

 with 4-Hz temporal resolution. 



c. Time series of pressure at approximately 150 cm above the bed with 

 4-Hz temporal resolution. 



d. Time series of pore fluid pressure at approximately 15 cm below the 

 bed with 4-Hz temporal resolution. 



e. Time series of vertical and cross-shore components of fluid velocity at 

 approximately 33 cm above the bed using an electromagnetic current 

 meter (EMCM) with 4-Hz temporal resolution. 



/ Video recording of ripple changes after wave runs. 



Analyses. 



a. Mean, minimum, maximum, and standard deviation of pressure, pore 

 pressure, fluid velocities, and sediment concentration data from OBS 

 sensors for each run. 



b. Mean of suspended concentration profiles for each run. 



c. Calculation of wave power spectrum with calibrated pressure data. 



d. Ripple dimensions from the image data of underwater video camera. 



The experiments were performed under a variety of forcing conditions, 

 i.e., accretionary and erosive waves, and monochromatic, narrow-band 

 random, and broad-band random waves. Conditions for the data runs are 

 tabulated in Table 10-1, in which H is zero-moment spectral wave height. 



Chapter 10 Intermittent Near-Bed Sediment Suspension 



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