gforcedfree: Calculates forced or free laminer conductance

In ilyamaclean/microctools: Various worker functions for microclimc package

Calculates forced or free laminer conductance

Description

Calculates forced or free laminer conductance

Usage

gforcedfree(d, u, tc, dtc, pk = 101.3, dtmin = 1)

Arguments

d	chacteristic dimension of surface (m)
u	wind speed (m/s)
tc	temperature (deg C)
dtc	estimate of temperature differences of surface and air, e.g. from previous time step (see details)
pk	atmospheric pressure (KPa). used for calculating molar density of air
dtmin	minimum tmeperature difference for calculating minimum conductance (see differenc)

Details

Calculates conductance under forced and free convection and selects whichever is greater. For conductance under free convection an estimate of the temperature difference between the air and surface is needed (usually from the previous timestep). Because the temperature difference in the previous timestep is used when conductance is under free convection, the model can de-stabalise as dtc approaches 0, leading to very low conductance and very high temperature differences in the current timestep. The parameter dtmin sets a minimum temperature difference, and prevents conductance being too low.

Value

conductance (mol / m^2 / sec)

Examples

# As function of `d`
d <- c(1:1000) / 100
g <- gforcedfree(d, 2, 11, 2)
plot(g~d, type = "l")
# As function of `u`
u <- c(1:200)/100
g<-gforcedfree(0.1,u,11,4)
plot(g~u, type = "l")

ilyamaclean/microctools documentation built on Jan. 25, 2023, 5:29 a.m.