Temperature and Windscale?
Posted: Wed Jan 23, 2019 3:49 pm
I noticed the windscaling factor changed dramatically on a cal ride this morning. The conditions were very calm, but COLD. Can temperature effect the calibration by as much as 20%?
Also, a while back. I "nerded" out on the physics, and came up with SF=(Avg Wheelspeed/Avg Windspeed)^2 for the scaling factor provided the original scaling factor was 1.000. It works perfect. If I apply the profile after adjusting this way, I get zero for ground wind speed for an out and back ride. It has worked out this way every time I have done it. It came from Pout=1/2*CdA*SF*rho*(v+vw)^3+mg*Crr*v and Pback=1/2*CdA*SF*rho*(v-vw)^3+mg*Crr*v. A simplification of a perfectly flat OB ride. vw=the ground speed of the wind, so Avg Windspeed=Avg Wheelspeed + vw.
Thanks,
Chris Maness
Also, a while back. I "nerded" out on the physics, and came up with SF=(Avg Wheelspeed/Avg Windspeed)^2 for the scaling factor provided the original scaling factor was 1.000. It works perfect. If I apply the profile after adjusting this way, I get zero for ground wind speed for an out and back ride. It has worked out this way every time I have done it. It came from Pout=1/2*CdA*SF*rho*(v+vw)^3+mg*Crr*v and Pback=1/2*CdA*SF*rho*(v-vw)^3+mg*Crr*v. A simplification of a perfectly flat OB ride. vw=the ground speed of the wind, so Avg Windspeed=Avg Wheelspeed + vw.
Thanks,
Chris Maness
