Yakhot's turbulent flame speed model is extended to include the effects of scales smaller than the laminar flame thickness (#x3B4;). An expression for the turbulent flame speed (ST) as a function of the turbulence intensity (u') and turbulent Reynolds number is derived. Good qualitative and fair quantitative agreement with experiment is obtained. It is found that at moderately high u', the small scales act to increase 5rover a #x201C;thin#x201D; flame at the same u' and that at very high u' these scales may actually cause a decrease in ST. In agreement with recent experimental observations, it is concluded that the effect of scales smaller than #x3B4; are probably significant for most flames at sufficiently high u'. It is argued that the high Reynolds number flames are in some respects simpler than low and intermediate Reynolds number flames because the application of the methods of statistical physics are possible in the former case.
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