Matched context for counterflow and back-flow

The page lists matched contexts for counterflow and back-flow.

Share - counterflow	Share - back-flow	Phrase
3.19%	27.51%	prevent {counterflow or back-flow} [perform operation]
2.93%	9.86%	fluid {counterflow or back-flow}
3.51%	4.08%	air {counterflow or back-flow}
1.48%	6.55%	fuel {counterflow or back-flow}