Which of the following meters is not associated with viscosity

Answer: Option D

In the context of fluid mechanics and viscosity measurement, the Orsat meter is not associated with viscosity. The Orsat meter is primarily used for the analysis of gas composition, particularly for measuring the percentage of carbon dioxide, oxygen, and other gases in a gas sample.

On the other hand:
Option A: Redwood viscometer is associated with measuring viscosity.
Option B: Saybolt viscometer is used for measuring the viscosity of petroleum products.
Option C: Engler viscometer is another instrument used for measuring viscosity.

Therefore, the correct answer is Option D: Orsat, as it is not related to viscosity measurement.