Grashof_number_Gates {TrenchR}

Grashof Number as in Gates (1980)

Description

The function estimates the Grashof Number, which describes the ability of a parcel of fluid warmer or colder than the surrounding fluid to rise against or fall with the attractive force of gravity (Gates 1980). The Grashof Number is estimated as the ratio of a buoyant force times an inertial force to the square of a viscous force.

Usage

Grashof_number_Gates(T_a, T_g, beta, D, nu)

Arguments

T_a

numeric Air temperature (C).

T_g

numeric Ground (surface) temperature (C).

beta

numeric coefficient of volumetric thermal expansion, beta = 3.67 x 10^-3 C^-1 in air and 41.9 x 10^-4 C^-1 in water.

D

numeric is characteristic dimension (e.g., body diameter) (m)

nu

numeric is the kinematic viscosity, the ratio of dynamic viscosity to density of the fluid (m² s^-1); can calculate from DRYAIR or WETAIR.

Value

numeric Grashof number.

References

Gates DM (1980). Biophysical Ecology. Springer-Verlag, New York, NY, USA.

See Also

Other biophysical models: Grashof_number(), Nusselt_from_Grashof(), Nusselt_from_Reynolds(), Nusselt_number(), Prandtl_number(), Qconduction_animal(), Qconduction_substrate(), Qconvection(), Qemitted_thermal_radiation(), Qevaporation(), Qmetabolism_from_mass_temp(), Qmetabolism_from_mass(), Qnet_Gates(), Qradiation_absorbed(), Qthermal_radiation_absorbed(), Reynolds_number(), T_sky(), Tb_CampbellNorman(), Tb_Gates2(), Tb_Gates(), Tb_butterfly(), Tb_grasshopper(), Tb_limpetBH(), Tb_limpet(), Tb_lizard_Fei(), Tb_lizard(), Tb_mussel(), Tb_salamander_humid(), Tb_snail(), Tbed_mussel(), Tsoil(), actual_vapor_pressure(), boundary_layer_resistance(), external_resistance_to_water_vapor_transfer(), free_or_forced_convection(), heat_transfer_coefficient_approximation(), heat_transfer_coefficient_simple(), heat_transfer_coefficient(), saturation_vapor_pressure(), saturation_water_vapor_pressure()

Examples

  Grashof_number_Gates(T_a   = 30,
                       T_g   = 35,
                       beta = 0.00367,
                       D    = 0.001,
                       nu   = 1.2)