A copper pipe (k = 350 W/m K) having inner diameter of 1.75 cm and 2.0 cm outside diameter conveys water and the oil flows through the annular passage between this pipe and a steel pipe. On the water side, the film coefficient is 4600 W/m² K and the fouling factor is 0.00034 m² K/W. The corresponding values for the oil side are 1200 W/m² K and 0.00086 m² K/W. Estimate the overall heat transfer coefficient between the oil and water?