When a critical fluid is brought into the unstable region in the presence of shear flow, growing fluctuations are greatly elongated in the flow direction, giving rise to strongly anisotropic light scattering. In the strong shear case the linear growth theory becomes applicable in a sizable time region 0 < t;:S te, in which the characteristic size along the flow direction grows as Dt/x, 1/x being the correlation length perpendicular to the flow in the strong shear case. For t;;:; te the

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... istic size in the perpendicular "directions starts to increase. By applying a computational method of Langer, Bar·on and Miller, it is found to increase as t a ' with a';::;O.2, whereas the characteristic size in the flow direction continues to increase roughly as t. § 1. Introduction . When a critical fluid is brought into the unstable region in the presence of shear flow, growing fluctuations are greatly elongated in the flow direction, giving rise to strongly anisotropic light scattering. In the strong shear case the linear growth theory becomes applicable in a sizable time region 0 < t;:S te, in which the characteristic size along the flow direction grows as Dt/x, 1/x being the correlation length perpendicular to the flow in the strong shear case. For t;;:; te the characteristic size in the perpendicular "directions starts to increase. By applying a computational method of Langer, Bar·on and Miller, it is found to increase as t a ' with a';::;O.2, whereas the characteristic size in the flow direction continues to increase roughly as t. §