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Cylinder Drag Coefficient:
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The drag coefficient (C_d) of a cylinder is a dimensionless quantity that describes the drag or resistance of a cylinder in a fluid environment. For an infinite cylinder in a steady flow, the approximate drag coefficient is 1.2.
The calculator uses the standard approximation for an infinite cylinder:
Where:
Explanation: This approximation is valid for Reynolds numbers between 10^3 and 10^5, which covers many practical engineering applications.
Details: Accurate drag coefficient calculation is crucial for designing structures in fluid flow, predicting forces on cylindrical objects, and optimizing aerodynamic performance in various engineering applications.
Tips: Enter the cylinder diameter and length in meters, fluid velocity in m/s, and fluid density in kg/m³. All values must be positive numbers.
Q1: Why is the drag coefficient approximately 1.2 for cylinders?
A: This value is derived from experimental data and represents the average drag coefficient for an infinite cylinder in steady flow at moderate Reynolds numbers.
Q2: How does Reynolds number affect the drag coefficient?
A: The drag coefficient varies with Reynolds number. At very low Re (<1), C_d can be much higher, while at very high Re (>10^5), it can drop significantly due to turbulent flow.
Q3: Does cylinder orientation affect the drag coefficient?
A: Yes, the drag coefficient differs significantly between flow parallel to the axis (much lower C_d) and flow perpendicular to the axis (C_d ≈ 1.2).
Q4: Are there limitations to this approximation?
A: This approximation is for infinite cylinders in steady flow. Finite length cylinders, surface roughness, and turbulent flow conditions can affect the actual drag coefficient.
Q5: How accurate is the 1.2 approximation?
A: For engineering purposes with Reynolds numbers between 10^3-10^5, this approximation is generally within 10-15% of experimental values for smooth cylinders.