Consider a Non-Newtonian drilling fluid (n = 0.523), flowing in a rectangular duct of width W = 4 in and height, H = 2 in. The density, flow rate, and dynamic viscosity of the drilling fluid are 1.7 g/cm', 150 gpm, and 124 cP, respectively. American Petroleum Institute (API) recommends using the following equation to determine the critical Reynolds mumber for typical drilling fluids: Rec = 3470 1370n, where n is Power Law flow behavior index. What type of fluid flow is observed?