In any forced or natural convection situation, the velocity of the flowing fluid is zero where the fluid wets any stationary surface. The magnitude of heat flux where the fluid wets a stationary surface is given by (a) k(Tₗᵤᵢ −Tₐₗₗ )
(b) k(dT)/(dy)∣ ₐₗₗ
(c) k(d²T)/(dy²∣ₐₗₗ
(d) h(dT)/(dy) ∣ₐₗₗ
(e) None of them
