Abstract:
Clouds are one of the major sources of uncertainty in climate prediction
(IPCC Fourth Assessment Report: Climate Change 2007). They play a significant
role in transporting heat across the whole extent of the troposphere. Cloud
formation and its development is a complex phenomenon, because of which until
recently no effective laboratory studies were done on clouds, because there was no
technique or apparatus that could handle those complexities (Stratmann et al.,
2009). Narasimha et al. (2011) were able to successfully reproduce a variety of
cloud forms occurring in nature. They presented “the transient plume subjected to
off-source diabatic heating” as an appropriate model for simulating cloud flows.
Taking lead from there, we planned to study the entrainment characteristics
of orographic clouds in laboratory. We modeled orographic clouds as diabatic,
planar turbulent, wall-jets. Validation of such a model would be easier in the field
compared to free standing clouds, as instruments can be placed along the terrain to
measure the actual flow conditions. Also, the two dimensionality of the planar
wall jet makes it closer analogue to an orographic cloud as they rise as a layer
hugging along the mountain slope. We subject this wall jet to volumetric hea
