Inclined Differential Manometer

In this type of manometer a narrow tube is connected to a reservoir at an inclination. The cross section of the reservoir is larger than that of the tube. Fluctuations in the reservoir may be ignored. As shown in Fig.L-8.6, the initial liquid level in both the reservoir and the tube is at o-o. The application of the differential pressure liquid level of the reservoir drops by Dh , whereas h is the rising level in the tube. Therefore

Since the volume of liquid displaced in the reservoir equals to the volume of liquid in the tube, we can define

Where 'A' and 'a' are the cross sectional areas of the reservoir and the tube respectively. Then the equation becomes    

In practice, the reservoir area is much larger than that of the tube; the ratio is negligible and the above equation is reduced to ; h = L sinq