afpt (version 1.1.0.4)

PowerToFroMechChem: Convert between mechanical and chemical power

Description

Functions convert between mechanical and chemical power

Usage

mech2chem(power.mech,bird,...)
chem2mech(power.chem,bird,...)

Value

Numerical value of either chemical power (mech2chem()) or mechanical power (chem2mech()).

Arguments

power.mech

Numerical value for mechanical power

power.chem

Numerical value for chemical power

bird

object describing the relevant morphological parameters of the bird (or bat); this object should be created using the Bird constructor.

...

optional arguments (none yet)

Author

Marco Klein Heerenbrink

Details

Chemical power is computed as $$P_\mathrm{chem} = R(\frac{P_\mathrm{mech}}{\eta} + \mathrm{BMR})$$ as described in Pennycuick 2008. Here \(R\) is the respiration factor, \(\eta\) is the muscle conversion efficiency and \(\mathrm{BMR}\) the basal metabolic rate, see Bird.

Mechanical power is simply calculated inversely: $$P_\mathrm{mech} = \eta(\frac{P_\mathrm{chem}}{R} - \mathrm{BMR})$$

References

Pennycuick, C. J. (2008). Modelling the flying bird. Amsterdam, The Netherlands: Elsevier.

See Also

computeChemicalPower

Examples

## Define a bird:
myBird = Bird(
  massTotal = 0.215, #  (kg) total body mass
  wingSpan = 0.67, #  (m) maximum wing span
  wingArea = 0.0652, #  (m2) maximum wing area
  type = "passerine"
)

## define a speed range
speedrange <- seq(5,14,length.out=5)

## compute aerodynamic power for that speed range:
Paero <- computeFlappingPower(myBird,speedrange)
Pchem <- Paero
Pchem$power <- mech2chem(Paero$power,myBird)
print(Pchem[c("speed","power","frequency","strokeplane")])
#   speed    power frequency strokeplane
# 1  5.00 15.60151  5.948083    46.56887
# 2  7.25 12.44362  5.948083    31.89129
# 3  9.50 12.79900  5.948083    22.51896
# 4 11.75 15.36721  5.948083    16.49120
# 5 14.00 19.82915  5.948083    12.09174

Pmech <- Pchem
Pmech$power <- chem2mech(Pchem$power,myBird)
print(Pmech[c("speed","power","frequency","strokeplane")])
#   speed    power frequency strokeplane
# 1  5.00 2.789751  5.948083    46.56887
# 2  7.25 2.129466  5.948083    31.89129
# 3  9.50 2.203773  5.948083    22.51896
# 4 11.75 2.740763  5.948083    16.49120
# 5 14.00 3.673714  5.948083    12.09174