The convection at the outer side of the greenhouse cover is modeled according to the experimental work of [1], who characterised the heat exchange coefficient at this saw-tooth surface as a function of the wind speed. The wind speed, being a boundary condition, is an input of the model. The main parameter is the cover tilt.
[1] G.P.A Bot. Greenhouse climate : from physical processes to a dynamic model. PhD thesis, Wageningen University, 1983.