phicontour {viadam}R Documentation

"Deflecting" angle of contour lines on a dam side

Description

Computes the “deflecting angle” of contour lines on a dam side from deflecting angle, slope of the terrain, and the angle of the dam side with respect to the terrain.

Usage

 
phicontour(phi,psi,alfa)

Arguments

phi deflecting angle with respect to the direction of steepest decent in a sloping coordinate system aligned with the terrain.
psi the slope of the terrain.
alfa the angle of the dam side with respect to the sloping terrain in the direction normal to the dam axis in a plane normal to the upstream terrain.

Value

phicontour returns a vector of angles with the same number of elements as phi, psi or alfa.

Note

The returned “deflecting angle” of the contour lines on the dam side is defined in the map plane.

This function is useful in an analysis of the flow of avalanches against natural obstructions where a “dam axis” is in many cases not easily defined. The returned “deflecting angle” of the contour lines may be compared with angles measured from maps and used to compute the deflecting angles phi and phih (see phi2phi) corresponding to a dam that is dynamically equivalent to the terrain obstruction.

The angles phi, psi and alfa are given in radians.

Author(s)

Tomas Johannesson

See Also

vdamheight, sdamslope, damangle and phi2phi.

Examples

## Not run: 
phicontour(25*pi/180,10*pi/180,40*pi/180)
## End(Not run)

[Package viadam version 1.0 Index]