shearVel: shearVel

In jasonfischer/rivSurveyR: A Package to Process Water Velocities Collected With SonTek Acoustic Doppler Current Profilers

Description

Calculates shear velocity from ADCP measurements

Usage

shearVel(ve, vn, vu = 0, depth, bcDepth, Dc, n, p = 1000,
  reference = "bottomCell", units = "metric")

Arguments

ve	A vector of velocities to the east, should be bottom cell velocity is reference is "bottomCell" and depth averaged velocity if reference is "mean"
vn	A vector of velocities to the north, should be bottom cell velocity is reference is "bottomCell" and depth averaged velocity if reference is "mean". Must be the same length as ve.
vu	A vector of vertical velocities, default is 0, should be bottom cell velocity is reference is "bottomCell" and depth averaged velocity if reference is "mean". Must be the same length as ve.
depth	A vector of depths, the same length as ve.
bcDepth	A vector containing the depth of the bottom cell, only needed if reference is bottomCell. Must be the same length as ve.
Dc	Sediment diameter of 90th percentile
n	Used to calculate local roughness height (Kc) Kc=n*Dc
p	Water density (kg/m^3)
reference	Method used to estimate shear velocity. If "mean" the Keulegan method is used where shear velocity = U/(1/k * ln(11* (depth/kc))), where U is the depth averaged speed, k is von Karman's constant (0.41), and, kc=n/Dc. For details see Garcia (2008). If "bottomCell" (the default) shear velocity = u/(9.5 * (h/kc)^(1/6)), where u is speed at h m above bottom. For details see Cheng-Lung (1991) and Simpson and Oltmann (1990).
units	Unit system of velocities, depths, and sediment diameters. Can either be "metric" (default) or "standard".

Value

A data.table containing shear velocity to the east (ustarE), shear velocity to the north (ustarN), shear speed (ustar), and shear speed heading (ustarHeading). The number of rows equals the number of observations in ve.

References

Garcia, M.H. 2008. Sediment transport and morphodynamics, chap. 2. In: Garcia, M.H. (Ed.), Sedimentation Engineering: Processes, Measurments, Modeling, and Practice No. 110. American Society of Civil Engineers, Reston, Virginia, pp. 21-163. Cheng-Lung 1991. <e2><80><9c>Unified Theory on Power Laws for Flow Resistance.<e2><80><9d> Journal of Hydraulic Engineering, Vol. 117, No. 3, March 1991, 371-389. Simpson, M.R. and Oltmann, R.N. 1990. <e2><80><9c>An Acoustic Doppler Discharge Measurement System.<e2><80><9d> Proceedings of the 1990 National Conference on Hydraulic Engineering, Vol. 2, 903-908.

Examples

data(vels)
#Use bottom cell velocities
shearVel(vels$BC.Vel.E, vels$BC.Vel.N, vels$BC.Vel.Up, vels$depth, vels$bottomCellDepth, Dc = 0.2032, n = 2)
#Use depth averaged velocities
shearVel(vels$Mean.Vel.E, vels$Mean.Vel.N, depth = vels$depth, Dc = 0.2032, n = 2, reference = "mean")

jasonfischer/rivSurveyR documentation built on May 18, 2019, 5:54 p.m.