Evaporation from porous surfaces into turbulent airflows: Coupling eddy characteristics with pore scale vapor diffusion

Abstract

.[1] Evaporative fluxes from terrestrial porous surfaces are determined by interplay between internal capillary and diffusive transport, energy input, and mass exchange across the landair interface. Turbulent airflows near the Earth's surface introduce complex boundary conditions that affect vapor, heat, and momentum exchange rates with the atmosphere. The impact of turbulent airflow on evaporation from porous surfaces was quantified using surface renewal theory coupled with a physically based pore scale model for vapor transfer from partially wet surfaces to individual eddies. The model considers diffusive vapor exchange with individual eddies interacting intermittently with a drying surface to quantify mean surface evaporative fluxes. The model captures nonlinearities between surface water content and evaporation flux during drying of porous surfaces, yielding close agreement with experimental results. This new diffusion-turbulence evaporation model provides a basic building block for improving estimation of field-scale evaporative fluxes from drying soil surfaces under natural airflows.Citation: Haghighi, E., and D. Or (2013), Evaporation from porous surfaces into turbulent airflows: Coupling eddy characteristics with pore scale vapor diffusion, Water Resour. Res., 49,[8432][8433][8434][8435][8436][8437][8438][8439][8440][8441][8442]

Reconciling the Reynolds number dependence of scalar roughness length and laminar resistance

“…When (see Figure b), r s l u ∗ ∼ R e k and the 1 scaling is recovered, as suggested by recent work [ Haghighi et al , ; Haghighi and Or , ] that assumed a balance between the vertical and horizontal diffusion. In our model, can only occur when the advection term does not play a role in the scalar budget ( ∂ s / ∂ x = 0) and thus molecular diffusion dominates.…”

“…In our model, can only occur when the advection term does not play a role in the scalar budget ( ∂ s / ∂ x = 0) and thus molecular diffusion dominates. Hence, our result is broadly consistent with previous work [ Haghighi et al , ; Haghighi and Or , ].…”

“…This important difference in the scaling is reflected in the most widely used parameterizations of scalar roughness length to date [ Yang et al , ; Chen and Zhang , ; Chen et al , , ; Zheng et al , ; Li and Bou‐Zeid , ]. Besides these two scaling laws, recent studies suggested a R e 1 scaling [ Haghighi et al , ; Haghighi and Or , ] and other empirically based scaling laws also exist [ Owen and Thomson , ; Zeng and Dickinson , ].…”

Microbial dispersal in unsaturated porous media: Characteristics of motile bacterial cell motions in unsaturated angular pore networks

“…In practice, Yamamura [2002] has shown that the travel time distribution of organisms, due to the fat-tailed dispersal kernels, is described reasonably well by the gamma distribution (a specific form of the inverse Gaussian distribution). Of available statistical distributions, the gamma distribution is well known and facilitates parametric and analytical modeling [e.g., Thom, 1958;Jury and Gruber, 1989;Husak et al, 2007;Haghighi and Or, 2013]. For our first passage time density results shown in Figures 7a and 7b, the KolmogorovSmirnov goodness of fit test confirms the suitability of the gamma probability distribution function:…”

Effect of near‐surface wind speed and gustiness on horizontal and vertical porous medium gas transport and gas exchange with the atmosphere

“…These authors, however, focused on a single fracture and did not include the effect of gusts. Haghighi & Or () and Haghighi & Or (,b) studied the distribution of wind‐induced water evaporation near obstacles on the soil surface. Investigations, however, included only surface evaporation and not vapour transport inside the soil.…”