I have had & use the swiss volcano stove for quite a few yrs,I have not seen any swirling effect via the ribbed design.I believe the ribs are there for ridgidity purposes alone,afterall they are military stoves built for the military rigors of abuse.If they were straight walled w/o the ribs,they would be creased/folded in short order upon the 1st bivouac!They are as Jim describes & bulky!I load mine up with tinder& wood & pack it into a gas mask pouch,usually slung over/around my main pack.I've observed hikers using them with alcohol burners,though I'm not an alky or gasser myself,I prefer a wood fire,I have gasser's & an Alky they don't get used much!