Bifurcation of homogenization and nonhomogenization of the curvature G-equation with shear flows

The level-set curvature G-equation, a well-known model in turbulent combustion, has the following form G(t )+ (1 - d div(DG/|DG|))(+ )(|DG| + V(X) <middle dot> DG = 0). Here the cutoff correction ()(+ )is imposed to avoid non-physical negative local burning velocity. The existence of the effective burning velocity has been established for a large class of physically relevant incompressible flows V in two dimensions [13] via game theory dynamics. In this paper, we show that the effective burning velocity associated with shear flows in dimensions three or higher ceases to exist when the flow intensity surpasses a bifurcation point. The characterization of the bifurcation point in three dimensions is closely related to the regularity theory of two-dimensional minimal surface type equations due to [31]. As a consequence, a bifurcation also exists for the validity of full homogenization of the curvature G-equation associated with shear flows.