𝑅? = 𝜌?? 𝜇 (4) In the equation, ρ is the density (either air or water), V is the free stream velocity, D is the diameter, and μ is the dynamic viscosity. The table below shows the calculated Reynold ’s number values for air versus water. Air Water Density (slugs/ft^3) 0.0024 1.94 Free Stream Velocity (ft/s) 29.64 2.933 Diameter (ft) 0.0417 0.0417 Dynamic Viscosity (lb-s/ft^2) 4.14E- 07 2.09E-05 Reynold's Number, Re 7088 11349 Table 2. Reynold’s Number (Air vs. Water) The Reynold’s number for air isn’t too far off from that of water. From that, we can assume that both types of flows are similar. The equation below is then used to solve for the drag force caused by water flow around the cylinder. 𝐹 𝐷 𝑤 = 1 2 ? 𝐷 𝜌? 2 ? (5) In the equation above, F D /w represents the drag force per unit length. The variable C D = 0.5322, ρ = 1.94 slugs/ft 3 , V = 2.933 ft/s, and D = 0.0417 ft. Thus, F D /w = 0.1815 lbs/ft.