Of Turbulence, Olfactory Sense, and Flatulence

Factual Questions
1

In the past, I’ve never been an especially gassy guy. But lately I’ve been doing the Atkins thing (my wife initiated the diet change, and dragged me in with her), and it’s poot city. These proteinacious foods really send my intestinal flora into methane overdrive, and the odor pins the needle on the stank-o-meter more often than I ever dared think possible. I offend even myself.

The frequency of flatus has increased alarmingly, and the rapid production of prodigious volumes of gas sometimes leaves me little time to run away where I can safely expell while at work. I know, I know, “quit the diet, numbnuts!” Look, I’m supporting my spouse. Plus, we have nothing but meat in the freezer now, anyway.

I work in a big open lab. One day, I really had to let rip but couldn’t get all the way to the mens’ room (I had things “cooking” on the bench, which required my close attention). My gut was in knots. I figured, hey, I’ll just run over to that corner over there where nobody is, try to look busy, vent, and then return to my station like nothing’s going on. I waited a good 5-10 seconds (all the time I could spare, really) before sauntering back to where I was, thinking I’d left the cloud of noxious fumes safely behind. But no! They followed me! Like some clinging comet of stink, I merely dragged a trail of putrid odor in my wake. My neighbor on the bench grunted and gasped as discretely as possible, but I knew I was busted. Ah, the ignominy!

Being an experimenter, I decided to investigate the problem in as good a model as I could contrive at home: A bowl of water, blue food coloring, and a honey-dipper. I would dip the honey-dipper in the water, and drop a bit of food coloring right next to it. Dragging the honey-dipper away from the dissipating cloud of blue seemed to corroborate my assumption: My motion through the air probably created a region of lower pressure behind my body, into which the gas would rush as I moved away. Small eddies of turbulence could be seen if I moved the dipper away quickly enough, and those seemed to mitigate the problem somewhat by creating a pull of their own, but not enough to stop an unacceptable portion of the cloud from trailing the dipper. Plus, when I scaled up the picture in my mind, I’d have to break wind someplace and sprint away for it to be all that effective, which is considered a dangerous practice in the laboritory. Spinning the dipping stick so as to rotate the dipper in place to create a vortex helped keep some of the color put, but I quickly realized I would have to twirl about so quickly to mimick the effect, it would cause little less embarassment than my stank-ass pollution.

So I wonder: Is it possible to leave a fart behind without waiting forever for it to diffuse? Is there some inoccuous kind of motion one can make as they leave the vicinity of the indiscretion that will leave the bulk of it behind? Is my only hope a steady diet of beano plus activated-carbon briefs? I appeal to the aero- and fluid- dynamicists to aid me in this most pressing physics problem.

Yours,

Stinkydude

2

Can’t you just back up to a fume hood?

3

I just wanted to say that I don’t have an answer, but I thoroughly enjoyed your question. And, I’m glad you on’t work next to me.

4

I wanted to do that, but somebody was working in the thing, as is often the case. It’s possible the stink could be pulled up into the cabinet and never reach the level of the nose, but there are risks involved. I mean, if I just walk up casually to somebody in the hood, as if I’m only there to make idle chit-chat, and the plan, er, backfires, that could be a more egregious offense than what I have already committed.

I should try it out, though, when the hood is unoccupied, and see if it’s effective. I wish I could plan for these things better to assure ideal conditions.

5

1.** “Beano”**
2. ** “Gas-X”**

6

You work in a lab, so find an excuse to light a Bunsen burner. Don’t stand too close.

7

Years ago, my company was preparing for the County Firemen’s Parade, and we labored long into the night getting trucks ready, along with food and beer breaks which rendered my GI system a cauldron of evil. In the morning, it was announced that the company dignitary I’d be driving was a fellow that I really disliked. He held me in similar favor.

Nothing was spoken as we crept along the parade route, yet as we approached the reviewing stand, the intestinal pressure cooker which was me needed to vent, and while staring straight ahead, a ‘growling dog under the couch’ poot was allowed to escape. On that humid June morning, the odor felt sticky. It had a color. My passenger managed a stage whisper, “You bastard,” out of the corner of his mouth, while maintaining military precision for the observers.

Once around the corner and enroute to the festivities, he hung his head out of the truck window, not unlike a pet dog. :smiley:

8

I have given this very question considerable thought. I think the answer is to be found in your pants. Specifically, some of the fart gas is trapped inside your garments and/or “sticks” to the fabric and diffuses out slowly. You can’t walk away from it any more than you could walk away from a stain on your pants. You just have to wait until it dissipates. Fortunately, farts dissipate a lot faster than stains.

I experience an amplification of this effect with my chair. If I fart a lot, then stop, the smell goes away quickly. But if I get up from my chair an hour or so later, the residual fart trapped in the small spaces between my ass and the chair, as well as the fabric and foam of the chair itself, gets released. This can cause disdain if a colleague is in my office.

You could probably lessen the fart-trapping effect by freeballing it. Or you could go to work buck naked, if your lab has “casual Fridays”.

9

I just thought of another thing, which I really don’t want to go into in any detail. Sometimes farts can be rather, shall we say, humid. I’m not talking trouser chili, just damp. That’s got to leave something semi-permanent on your shorts. Now, we’ve all done this at least once (maybe not since childhood), but if you take a whiff of your underwear crotch after a typical day’s flatular activity, it doesn’t exactly smell like Chanel No.5. I believe that has some significance.

10

I am lost in admiration for someone who actually went and performed an experiment to find this out. Semper the Fight Against Ignorance, dude. :smiley:

Anyway, it’s interesting that you proved something that I, as a lactose-deficient person, have always known–there will be a cloud of stink that follows you after your supposedly discreet fart in a corner somewhere, unless you’re careful to stand there for a fairly long minute and allow it to dissipate, and then move away slowly.

And it’s only the “humid” farts that seem to do this (small discreet dry “poots” don’t seem to follow you around quite as much, even though the dry poots can sometimes be qualitatively more pungent), but I don’t think it has anything to do with leaving something on your shorts, I think it’s more a factor of the way that humid air carries odors better than dry air.

I even found a cite for this, sort of.

http://starryskies.com/articles/dln/5-96/rain.html

Uh huh.

11

Sulphur

Yes, Sulphur. Burning a sulphur candle WORKS!
A bit hazardous if burned too long.

Much easier to get some old fashioned kitchen matches in the big box.
Light one or two or even three if stench is bad.

Any kind of matches will do bu the smaller ones take more to do the job.

Don’t strike them to close to a source of GAS! :slight_smile:

12

Some kind of bung might be in order.

13

As a practicing physician, I must concur with spingears and say BEANO. Works better than gas-x.

Get beano. Use it. Lots of it.

Wish I had the smarts to discuss the turbulence mathematics of gas, tho.

14

Well, QtM, I do have the smarts for it, so I’ll step in for you here, as one of the board’s resident aerodynamicists. But don’t worry, I won’t be trying to usurp the physiological questions. :wink:

Probaby the best thing you can do would be to walk sideways. Assuming your fore-aft dimension is less than your port-starboard span, this will be effective. The reasons are really twofold.

  1. Moving through the air with your narrowest dimension showing will greatly reduce the huge turbulent wake that you leave behind you. You’re definitely more aerodynamic from the side.

  2. The air will actually blow across your ass this way, having the same effect that a very slight breeze would. This will continuously replace the odiferous air next to your ass with fresh air. If you walk normally, your farts are just trapped in the pocket of stagnant air behind you, as your experiment showed.
    But how can you walk normally and avoid stinking up the place? If you look at page 44 of this paper, you’ll see that the best thing you can do is move exceedingly slowly (very low Reynolds number), or really fast (very high Reynolds number). It’s the intermediate speeds which have the large turbulent wakes. Of course, those are circular cylinders in crossflow, and most people aren’t cylinders. But the idea is still appropriate.

The Reynolds number that applies to a walking person is about 25,000, give or take a few thousand. That number corresponds to figure (d) on that above page (10[sup]3[/sup] < Re < 10[sup]5[/sup]). That is the one with the biggest turbulent wake, and that’s why the farts carry so well.

So if you don’t want to take 45 minutes to get across the lab, or you don’t want to run at about 150 mph, your best best is to turn sideways, and keep your butt out of the turbulent wake.

15

I still contend that you won’t be able to walk away from the stench. The principle is the same as why hair keeps you warm - the air trapped amongst the hairs stays next to your body as you move, allowing it to act as insulation. An appreciable amount of fart gas is going to stay trapped in Loopydude’s clothes and butt hair as he moves around, acting as a “stink accumulator” so that the emission of fart molecules is smoothed out over time.

Hats off to Loopydude. Would that my officemate took a similar interest in mitigating the effects of his flatulence.

16

One of the things I like about Atkins is my almost total lack of gas I have now.
::: shrugs:::
Before I started Atkins I was just like what the OP decribes now.

17

Also about Atkins - do you eat alot of “sugar free” foods with Sugar Alcohols in them? (sorbitol, malitol, lacitol, etc)

Those are like/are really laxitives and they will give you gas, bloating and stomach cramps. and gas. and alot of bloating. and gas. stinky gas, too.

I’ve found (through talking with other low carb folks) that everyone reacts differently to SAs. Some has little effect, and for some it sends them to colvulsions on the toilet.

Also if you’re doing Atkins you’re eating more delicious veggies than ever before (right? you should be…) Broccoli is an especially gaseous veggies. I think dark green leafies are too. There may be others…

And if you’re eating more cheese than before, that might be a problem. You may have even BECOME lactose intolerant.

Anyway, you might want to also take a look at what you eat and get rid of the stank poblem at the source.

18

Made it to the men’s room that last time. Phew. What’s great was, I was at the urinal, but somebody else was in one of the stalls. So neither one of us can see each other, and I can blast away incognito. Even better, I’m washing my hands and another guy walks in: As he enters through the door, I get that flash of dismay on his face as he is reflected in the mirror, before he turns his back to me. Who was the most likely culprit? Me, or the guy in the stall?

I’m not above framing the innocent.

Anyway, Zipper, you nailed it: Along with copious meat and fat, I’m eating plenty (much more so these days, now that induction and the first phase is over) of complex carbs. The effect has been roughly akin to going from atomic to thermonuclear. And yes, broccoli is the absolute worst. Asparagus isn’t so much a gas producer as a rank odiferous, but it also gets me into trouble. I’m not sure about baby spinach and eggplant, but shitake and portobello mushrooms also produce high-yield, weapons-grade outgassing. I don’t even dare to approach legumes. A mere whiff might turn me into a human incendiary. I’d suggest my colon for the Pentagon’s non-lethal weapons programme, but I’m unsure of how reliable the “non-lethal” qualifier is.

The more I read, the more I realise Atkins (and the like) are almost tailor-made to produce flatulence: Add lots of protein and fat to a meal full of hard-to-digest complex carbs, and it’s like some 3rd world WMD conspiracy. The fiberous materials pass right throught he stomach largely unperturbed, to be muched on happily by sundry colonic flora, which produce, as waste, what seem to be litres of CH4 and CO2. It doesn’t help that the fat seems to grease the chute, so to speak. Now add the protein; just full of those vile sulfhydryls and thioesters (I wonder if some meats are known to have significantly more cystein and methionine than others?), it is clearly the biggest source of the olfactory offensiveness.

Some good advice above. A working game plan is to:

A) Purchase lots of Beano, perhaps the world’s supply, and make it a staple of any meal.
B) Following audilover’s wonderful response to my basic question, try to side-step out of the Cloud of Death slowly and carefully.
C) Run to the fume hood whenever possible (per got passwords).

Oh, yeah, regarding item C above: The fume hood does indeed seem to draw air with enough force in its immediate vicinity to make a noticible difference, as I confirmed on a couple occasions (though an n of 2 does not provide a large enough sample-size to say my observation is significant; plus the study is hardly “blinded”, even with watering eyes).