A part of building physics deals with dynamics of motion of gases (e.g. air) and liquid (e.g. water) of buildings (and their components), and things and people within and surrounding the buildings. Buildings and cities become much bigger, higher and deeper (into the ground) at an unprecedented rate. Our knowledge about human body needs in comfort and hygiene (clean water, air, surfaces and objects) also grows. These challenges introduce new fluid dynamics problems, so do the new products and processes introduced into buildings. As these new problems continue to emerge, so are the opportunities for innovation and design. Most traditional building fluid problems have been dealt with since the establishment of the boundary layer theory (Prandtl, 1904) and CFD (Richardson, 1922), such as air/water flows in ducts/pipes/pumps, ventilation jets, wind loading, infiltration, door way/chimneys flows, fire and smoke flows, air distribution, etc. Primary fluid problems are mostly environmental in nature, e.g. with regarding to air environment ranging from exhalation puff (1cm), human body (1m), buildings (10-100m), neighborhood (1km), and cities (10-100km). Secondary problems are mostly industrial in nature, such as in efficient HVAC, water supply and drainage system, and building and city fires. Nowadays, those building environment problems receive perhaps the most attention. Fluids may be one component or a solution of a problem in building physics or technologies, and sometimes, may not be fully recognized in the first instant. Emerging fluid problems are mostly multi-scale, multi-physics/chemistry and multi-domain. Here I shall discuss some examples that I am familiar with, including shaking and blowing out of fine virus particles from surfaces (100nm), exhalation puff for droplet transmission (1cm), multiple states in natural ventilation and smoke flows (10-100m, building scale), extremely high-Ra natural convection along a high-rise building wall (100m), and urban plume induced flows for city climate and environment (1km, city-scale), and the latter extends us into the arena of city physics and technologies.

IBPC 2015 theme: Building Physics for a Sustainable Built Environment

Keynote speaker