December 2nd, 2023

"Unveiling surface-subsurface flow interactions of a salmon redd" (Hilliard et al. 2025, DOI: 10.1016/j.advwatres.2025.104947)

Advances in Water Resources


This README file contains descriptions of nomenclature used for the time-averaged SPIV measurement data, which depicts
the surface flow characteristics. On HydroShare, the data is split into two folders which signify whether the data is for the
smooth salmon redd or rough salmon redd experiments. Within each folder are appropriately-named CSV files (separated by semi-colon), which contain 30 flow-relevant parameters, as well as appropriately-named vector images of the longitudinal (streamwise, u) velocity field for all four flow cases. Each row in the CSV files represents one grid point, or SPIV interrogation window. The columns are organized by rows of grid points from the original FOV, i.e., the first row of grid points is listed (top row; constant y, decreasing x), immediately followed by the second row of grid points, third row, fourth row, etc. In both the CSV and PNG files, flow is from right to left.


Abbreviations:
	SPIV - Stereo Particle Image Velocimetry
	SS - Slow & Shallow (Flow case)
	FS - Fast & Shallow (Flow case)
	SD - Slow & Deep (Flow case)
	FD - Fast & Deep (Flow case)
	USBC - Upstream Boundary Condition (Spatial data acquisition location)
	RL4 - Redd Location #4 (Spatial data acquisition location)
	Vx - Longitudinal, or streamwise, velocity component (u)

30 parameters (and their [units]) listed in the CSV files, which contain time-averaged SPIV data:
	x [mm] - X-position (X = 0 at redd start)
	y [mm] - Y-position (Y = 0 at water surface)
	Velocity u [m/s] - Longitudinal (streamwise) velocity component
	Velocity v [m/s] - Vertical (normal to sediment bed) velocity component
	Velocity w [m/s] - Transversal (cross-stream) velocity component
	Velocity V [m/s] - Velocity resultant
	du/dx [1/s] - Longitudinal (streamwise) velocity component gradient w.r.t longitudinal (x) direction
	du/dy [1/s] - Longitudinal (streamwise) velocity component gradient w.r.t vertical (y) direction
	dv/dx [1/s] - Vertical (normal to sediment bed) velocity component gradient w.r.t longitudinal (x) direction
	dv/dy [1/s] - Vertical (normal to sediment bed) velocity component gradient w.r.t vertical (y) direction
	dw/dx [1/s] - Transversal (cross-stream) velocity component gradient w.r.t longitudinal (x) direction
	dw/dy [1/s] - Transversal (cross-stream) velocity component gradient w.r.t vertical (y) direction
	w_z [1/s] - Vorticity of flow (dv/dx - du/dy)
	|w_z| [1/s] - Absolute value of w_z
	div 2D [1/s] - 2D Divergence of flow (du/dx + dv/dy)
	L_ci [1/s^2] - 2D swirling strength
	N [-] - Number of vectors (samples)
	Rxx [m^2/s^2] - Reynolds stress x-x (1-1)
	Rxy [m^2/s^2] - Reynolds stress x-y (1-2)
	Rxz [m^2/s^2] - Reynolds stress x-z (1-3)
	Ryy [m^2/s^2] - Reynolds stress y-y (2-2)
	Ryz [m^2/s^2] - Reynolds stress y-z (2-3)
	Rzz [m^2/s^2] - Reynolds stress z-z (3-3)
	SD Vx [m/s] - Standard deviation of Velocity u
	SD Vy [m/s] - Standard deviation of Velocity v
	SD Vz [m/s] - Standard deviation of Velocity w
	Unc V [m/s] - SPIV measurement uncertainty of velocity resultant V
	Unc Vx [m/s] - SPIV measurement uncertainty of longitudinal (streamwise) velocity component (u)
	Unc Vy [m/s] - SPIV measurement uncertainty of vertical (normal to sediment bed) velocity component (v)
	Unc Vz [m/s] - SPIV measurement uncertainty of transversal (cross-stream) velocity component (w)