I was pumping completely perpendicular to the wind the other day and was thinking, is it equivalent to pumping in no wind, or is there more drag?
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All things equal maintaining your line with side wind is going to take more power than if there were no wind. your apparent wind will be coming at an angle and you are going to exert force to maintain that line and not get blown downwind. Same concept as when cycling pelotons form an echelon (diagonal paceline) when going into a side wind.
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I do understand that, but if you were going in the x direction at a speed v_x, and the wind was going in the y direction at a speed w_y, your apparent wind would be the vectorial sum of both, and the wind you are going “against” would only be at v_x speed.
If w_y was 0 (no wind scenario), you would still be going “against” a wind of v_x speed.
Am I missing something?
Yes, but there is additional input necessary to hold your line against the wind from the y direction. Your apparent HEADWIND speed would be the same in both scenarios, but in addition to overcoming that headwind you would have to exert force to counteract the side wind. If you look at power output you are expending additional watts to hold your line in a side wind. The equivalent wattage output with a side wind would be bearing off very slightly.
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Thanks! It’s clear now. Also I didn’t take into account that wind drag is proportional to v^2 and therefore it wouldn’t be just the components v_x + w_y but (v_x + w_y)^2, so a pretty big difference (2*v_x*w_y)!
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I may not do formulas, but I understand apparent wind / yaw. haha.
I spent many years racing bicycles and the move to open up a gap in a side wind is riding the curb on the farthest downwind side of the road to maximize the paceline’s exposure to the sidewind (“guttering” the field). Not an exact analog to this concept, but still applicable.
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yeah, I think so. Drag force is relative to velocity squared. So although the headwind is the same, the total drag is increased. I’m not exactly sure how that plays out, but I’ve experienced it and a side wind definitely has an impact. I’ve also noticed a big difference in the condition of the top foot or so of water being impacted by wind. Pumping in glassy conditions is totally different than a tail wind that perfectly matches my speed. Same aerodynamic drag, but different conditions in the water
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