The vertical-velocity skewness in the atmospheric boundary layer without buoyancy and Coriolis effects

Journal Article · Thu Nov 14 00:00:00 EST 2024 · Physics of Fluids

DOI:https://doi.org/10.1063/5.0235007· OSTI ID:3006758

Buono, Elia ^[1]; Katul, Gabriel ^[2]; Heisel, Michael ^[3]; Poggi, Davide ^[4]; Peruzzi, Cosimo ^[5]; Vettori, Davide ^[4]; Manes, Costantino ^[4]

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1. Duke Univ., Durham, NC (United States); Polytechnic University of Turin (Italy)
2. Duke Univ., Durham, NC (United States)
3. Univ. of Sydney, NSW (Australia)
4. Polytechnic University of Turin (Italy)
5. Italian Institute for Environmental Protection and Research (ISPRA), Rome (Italy)

One of the main features of near-neutral atmospheric boundary layer (ABL) turbulence is the positive vertical velocity skewness $$Sk_w$$ above the roughness sublayer or the buffer region in smooth-walls. The $$Sk_w$$ variations are receiving renewed interest in many climate-related parameterizations of the ABL given their significance to cloud formation and to testing sub-grid schemes for Large Eddy Simulations (LES). The vertical variations of $$Sk_w$$ are explored here using wind tunnel and flume experiments collected above smooth, rough, and permeable-walls in the absence of buoyancy and Coriolis effects. These laboratory experiments form a necessary starting point to probe the canonical structure of $$Sk_w$$ as they deal with a key limiting case (i.e., near-neutral conditions). Diagnostic models based on cumulant expansions, realizability constraints, and constant mass flux approach routinely employed in the convective boundary layer as well as prognostic models based on third-order budgets are used to explain variations in $$Sk_w$$ for the idealized laboratory conditions. The failure of flux-gradient relations to model $$Sk_w$$ from the gradients of the vertical velocity variance σ$$_w^2$$ are explained and corrections based on models of energy transport offered. Novel links between the diagnostic and prognostic models are also featured, especially for the inertial term in the third-order budget of the vertical velocity fluctuation. The co-spectral properties of w′/σ_w vs w′²/σ$$_w^2$$ are also presented for the first time to assess the dominant scales governing $$Sk_w$$ in the inner and outer layers, where w′ is the fluctuating vertical velocity and σ_w is the vertical velocity standard deviation.>

• Research Organization: Univ. of California, Los Angeles, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: SC0022072
• Other Award/Contract Number: NSF- AGS-202863; BECCA-ALCOTRA; 101022685
• OSTI ID: 3006758
• Journal Information: Physics of Fluids, Journal Name: Physics of Fluids Journal Issue: 11 Vol. 36; ISSN 1089-7666; ISSN 1070-6631
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

Boundary layer flow
Turbulence theory and modelling