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I have a problem with wind direction

Wed, 05/09/2018 - 2:01am — MostafaS
Hi, I have a problem with wind direction. When I consider the direction of the wind in the same direction of flow in the reservoir, the concentration of pollution is decreasing, while it should increase. I ask you to answer that this problem is related to Which part? thank you
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Water Quality
Wed, 05/09/2018 - 8:58am — Amir

Page A-58: Segment and wind orientation are illustrated in Figure A-28 and Figure A-29. The angles are measured in radians clockwise from north. A wind from the east would have an angle of π/2 radians, π radians from the south, 3π/2 radians from the west, and 0 or 2π radians from the north.
Thu, 07/19/2018 - 1:51pm — Jeremy

Amir, this isn't adding up to me--maybe I'm coming at this from the wrong direction. clockwise from north for wind that is going south creates a vector that is pi(). a vector blowing from west to east is pi()/2, while wind from the east would be 3pi()/2. Figure A-29 supports this interpretation, no?

Tue, 10/09/2018 - 1:48pm — Ertugrul

Both figures in the manual are confusing because of the big "North" arrows. The whole thing looks like it is in 3D (reminding me the right-hand rule), which is not the case. For both figures, if you draw X and Y coordinates in 2D first, then locate your wind vector (or segment direction) as the tip of the wind vector/arrow (or segment downstream end/tip) touches the intersection of X and Y coordinates, i.e., point (0,0), everything will make sense.