polykin.transport.flow¤
Cd_sphere ¤
Cd_sphere(Re: float) -> float
Calculate the drag coefficient of an isolated sphere.
For laminar as well as for turbulent flow, the drag coefficient is given by:
\[ C_{d} = \frac{24}{Re} \left(1 + 0.173 Re^{0.657}\right)
+ \frac{0.413}{1 + 16300 Re^{-1.09}} \]
where \(Re\) is the particle Reynolds number.
References
- Turton, R., and O. Levenspiel. "A short note on the drag correlation for spheres", Powder technology 47.1 (1986): 83-86.
PARAMETER | DESCRIPTION |
---|---|
Re
|
Particle Reynolds number.
TYPE:
|
RETURNS | DESCRIPTION |
---|---|
float
|
Drag coefficient for an isolated sphere. |
See also
vt_sphere
: related method to estimate the terminal velocity.
Examples:
Calculate the drag coefficient for a tennis ball traveling at 30 m/s.
>>> from polykin.transport import Cd_sphere
>>> D = 6.7e-2 # m
>>> mu = 1.6e-5 # Pa·s
>>> rho = 1.2 # kg/m³
>>> v = 30. # m/s
>>> Re = rho*v*D/mu
>>> Cd = Cd_sphere(Re)
>>> print(f"Cd = {Cd:.2f}")
Cd = 0.47
Source code in src/polykin/transport/flow.py
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