Izvorni znanstveni članak
A METAMODELLING IMPLEMENTATION OF A TWO-WAY COUPLED MESOSCALE-MICROSCALE FLOW MODEL FOR URBAN AREA SIMULATIONS
G. Tsegas
; Laboratory of Heat Transfer and Environmental Engineering (LHTEE), Aristotle University, Thessaloniki, Greece
Ph. Barmpas
; Laboratory of Heat Transfer and Environmental Engineering (LHTEE), Aristotle University, Thessaloniki, Greece
I. Douros
; Laboratory of Heat Transfer and Environmental Engineering (LHTEE), Aristotle University, Thessaloniki, Greece
N. Moussiopoulos
; Laboratory of Heat Transfer and Environmental Engineering (LHTEE), Aristotle University, Thessaloniki, Greece
Sažetak
Systems of coupled prognostic mesoscale and microscale models have been used as a tool to accurately simulate flows
around artificial structures and over densely-built urban areas. Typical implementations of such systems are based on a one-way
coupling scheme, where the mesoscale model provides initial and boundary conditions for each off-line application of the
microscale model. While very successful in predicting steady-state flows within specific local-scale areas, such schemes fail to
account for feedbacks on the mesoscale flow induced by the presence of structures in smaller scales. Unfortunately, the large gap of
spatial and temporal scales practically prohibits parallel on-line execution of the mesoscale and microscale models for any
significant time interval. It is therefore necessary that a simplifying approach is adopted, where the microscale feedback is spatially
and temporally upscaled to interact with parts of the mesoscale domain covering the urban area. In the present work a two-way
coupled model system is developed, consisting of the prognostic mesoscale model MEMO and the microscale model MIMO. The
microscale feedback on the mesoscale domain is simulated using a metamodelling approach, where the effect of local flows on the
vertical profiles is estimated for representative urban areas of sizes up to a few hundred meters and used as calibration input for a set
of interpolating metamodels. The feedback from the microscale metamodels is then introduced back in the mesoscale grid by means
of Newtonian relaxation. As an illustrative application, simulations for the city of Athens, Greece during a multi-day period are
presented. Effects of the microscale feedback on the mesoscale flow become evident both as a reduction of lower-level wind speeds
in urban cells as well as an overall increase in turbulent kinetic energy production over densely-built areas.
Ključne riječi
metamodelling; urbanisation,mesoscale; microscale; two-way coupling
Hrčak ID:
64237
URI
Datum izdavanja:
12.12.2008.
Posjeta: 936 *