Along the Mt Vernon trail, north of National Airport, there is a bank of port-a-potties. Normally, port-a-potties are a temporary solution, but these crappers have been in the same location for as long as I remember. It doesn't take long for a port-a-potty in DC to get fouled up....sometimes I think they drop them off at events full of poo. So, to keep these in tolerable condition, I'm sure the shitsucker is at this location on a very frequent basis.
Everyday, I pass this wall of crappers. In the morning, I usually smell nothing. On the ride home, I catch a whiff of poo that nearly knocks me off the bike. What is unusual to me is the point at which I smell the poo. I'd expect to detect the smell just before passing the crappers, and holding that smell until just a few feet after passing them. Instead, I detect the smell about 50ft after I pass the wall of crap. I've been trying to understand this phenomenon, and have came up with a couple of explanations. The simplest explanation is that the winds are blowing the stench, but this seems to happen on days that are not windy. So, it's not that simple. This got me to thinking that there may be a sort of "smell Doppler" effect that can explain the existence of an odor vector. See the diagram below.
If there is indeed a smell Doppler effect, the odor vector would vary based upon my speed. I may need to test this on future rides. By detecting the variations due to speed, I may be able to calculate an escape velocity....the speed at which I'd need to travel to not detect the odor. I don't know if breaking the "Smell Barrier" will be achievable by bicycle, but I hope to be the first.
Everyday, I pass this wall of crappers. In the morning, I usually smell nothing. On the ride home, I catch a whiff of poo that nearly knocks me off the bike. What is unusual to me is the point at which I smell the poo. I'd expect to detect the smell just before passing the crappers, and holding that smell until just a few feet after passing them. Instead, I detect the smell about 50ft after I pass the wall of crap. I've been trying to understand this phenomenon, and have came up with a couple of explanations. The simplest explanation is that the winds are blowing the stench, but this seems to happen on days that are not windy. So, it's not that simple. This got me to thinking that there may be a sort of "smell Doppler" effect that can explain the existence of an odor vector. See the diagram below.
If there is indeed a smell Doppler effect, the odor vector would vary based upon my speed. I may need to test this on future rides. By detecting the variations due to speed, I may be able to calculate an escape velocity....the speed at which I'd need to travel to not detect the odor. I don't know if breaking the "Smell Barrier" will be achievable by bicycle, but I hope to be the first.
12 comments:
* Doppler may not be the right word you are seeking. Doppler implies some change due to speed of travel (changing sound, red/blue shift in light, etc.). This would imply the smell changes due to your speed. Not what you are trying to imply.
* Smell is detected once the odor/particles hit your nose/mouth. A very small area.
* Seems not to add up to me. Unless there's a pile of excrement after the portajohns.
I believe it is the correct word. There is a manipulation of the smell vector wrt my speed. Maybe this would best be demonstrated by drawing the variations in stink lines at different speeds. I smell nothing while parallel to the crappers at 20mph
The stink is the exact same smell you expect, only at a different location. It is not as though the stink now smelled like roses. That's what Doppler would mean with sense of smell. Just as a train emits the same frequency, but it appears different to the listener as it changes.
I'm saying sense of smell is localized. Therefore my hypothesis is that it is entirely a wind phenomenon--unless there has been some spillage of crap outside the portajohn area.
but it happens regardless of wind. even when the wind is blowing against the direction of travel, i still smell it after passing it.
i'm arguing there is a manipulation of the odor vector.
not arguing that smell = sound waves, but by the fact that my velocity has something to do with this, and it's distorting the standard stink lines that should emit radially from the shitters, i'm calling it "smell doppler"...my own term.
my question is that if this is dependent on velocity of the rider, is it possible to "break the smell barrier" by reaching a speed that outruns the smell?
I agree there must be some manipulation of the smell vector. Just saying that "Doppler" implies a shift of what you smell, not where you smell it.
I don't think what you're saying is true as far as a smell barrier goes. I think the smell has just been moved to a different location. The time you smell it is basically the time you are within the stink zone. So if you're going fast enough but still pass within the stink zone, you'll still smell it for a fraction of a second.
I actually think what you're observing is MORE likely on a day that's not windy.
it happens EVERY day. the wind has nothing to do with it.
on Friday I snapped this picture from the smell detection point. calm winds...i smelled it as i passed while riding at this very point, then rode back to snap the picture. i didn't smell it when i stopped here.
are you saying that somehow i'm "pushing the smell"?
on a calm day, i should ride by this at various speeds. have an assistant mark the location where i first detect the smell. then i can measure the smell vector. then, i can calculate the speed i'd need to reach in order to break the smell barrier.
or are you saying that particles of shit are entering my nose as i pass, and my brain doesn't detect until later?
I'm suggesting both of those variables are possible.
Seems like you have to measure the difference while traveling the same speed on windy day versus a non-windy day. And then change your speed during constant wind.
if i did during a windy day, i'd have to try at various windspeeds and directions. truly doesn't seem to be wind-dependent. the wind direction doesn't really matter...every day i smell it past the port-a-potties.
That implies to me that you speed alters when your brain detects the smell.
i'm arguing a wave theory of smell propagation.
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