抄録
This paper presents turbulent structures of thermally-stratified boundary layer using results of direct numerical simulations (DNSs) for a spatially developing boundary layer. In the previous study (Hattori et al., 2007), we indicated fundamental turbulent statistics of boundary layer flow with various thermal stratifications by means of DNS. DNSs show fascinating results, in which the counter-gradient diffusion phenomena (CDP) in turbulent momentum and heat transfer are observed in the strongly-stratified stable boundary layer It is well-known that the counter-gradient diffusion phenomenon disturbs the transport of turbulent quantities due to reductions of the effective diffusivities for momentum and heat. However, it is not yet fully understood how and why CDP occur in strongly-stratified stable turbulent flows. The objectives of this study are to investigate turbulent structure in specially developing thermally-stratified turbulent boundary layers.