Toward Numerical Modeling in the “Terra Incognita”

Wyngaard, J. C.

doi:10.1175/1520-0469(2004)061<1816:tnmitt>2.0.co;2

Cited by 570 publications

(528 citation statements)

References 32 publications

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“…The relation from equation (38) is valid for the stability coefficients of Dyer, given in equation (12). If the stability coefficients are kept implicit, the relation for Cε,3 becomes more cumbersome.…”

Section: Methods I: Solution Of Alinot and Massonmentioning

confidence: 99%

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A new k‐epsilon model consistent with Monin–Obukhov similarity theory

2016

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A new k-ε model is introduced that is consistent with Monin-Obukhov similarity theory (MOST). The proposed k-ε model is compared with another k-ε model that was developed in an attempt to maintain inlet profiles compatible with MOST. It is shown that the previous k-ε model is not consistent with MOST for unstable conditions, while the proposed k-ε model can maintain MOST inlet profiles over distances of 50 km.

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Section: Methods I: Solution Of Alinot and Massonmentioning

confidence: 99%

“…For ζ → 0, the assumptions of MOST also lead to the neutral ASL solution, with Φm(0) = Φ h (0) = 1, where both the heat flux and the gradient of the potential temperature are zero. The Boussinesq approximation [11] is used to parameterize the deviatoric Reynolds stresses [12] …”

Section: Monin-obukhov Similarity Theorymentioning

confidence: 99%

A new k‐epsilon model consistent with Monin–Obukhov similarity theory

2016

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“…Hence, although fully aware of the potential drawbacks (e.g. Wyngaard, 2004; also Figure 12 for domain 4. The x locations also correspond for both domains and show part of the domain approximately from the mountain top (east limit) to the west over the sea (compare x axes of (b) and Figure 12 for exact locations).…”

Section: Generating Mechanisms Of Pulsationsmentioning

confidence: 99%

Numerical simulation of pulsations in the bora wind

Belušić

Žagar

Grisogono

2007

Quart J Royal Meteoro Soc

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Numerical simulation of a long bora episode is presented and compared with measurements. The goal is to resolve the quasi-periodic oscillations of the bora gusts, i.e. the pulsations. The model reproduced well the approximately 7 min periodicity of pulsations and the upstream structure of the atmosphere, and can thus be used for the detailed dynamical considerations.The results of previous studies are confirmed, as well as the hypotheses on the mechanisms responsible for the disappearance of pulsations. Specifically, it is shown that the upper-tropospheric jet induces strong positive shear throughout the troposphere and consequently the local nonlinearity of the incoming flow weakens. Henceforth, the low-level wave breaking is diminished and so the pulsations cease. From the three previously proposed generating mechanisms of pulsations, the results obtained point to the Kelvin-Helmholtz instability as the primary mechanism in this case.Additionally, it seems that the situations with absence of pulsations may be related to the formation of the mountainwave-induced rotor.

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“…resolutions or "terra incognita" was coined to describe the spatial scales O(10 2 − 10 3 ) m at which Navier Stokes is able to resolve a substantial fraction of the kinetic energy in the atmospheric boundary layer (ABL), while still needing to model the 25 remaining part with physical parameterizations (Wyngaard, 2004). Under the first coupling approach, the GZ is avoided but turbulence generation methods must still be applied to the meso scale fields before they can be used as driving inflow to LES (Haupt et al, 2015;Mirocha et al, 2013).…”

Section: Durationmentioning

confidence: 99%

Analysis of Different Gray Zone Treatments in WRF-LES Real Case Simulations

Doubrawa

Montornès²,

Barthelmie

et al. 2018

Preprint

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Abstract. When conducting meso-micro scale coupled atmospheric simulations, it is crucial to ensure an adequate treatment of gray zone or terra incognita resolutions in which a large portion of the kinetic energy is naturally produced by the momentum balance equations in the model, while the remaining part still needs to be parameterized. In this work, we conduct three multiday, real case, full-physics atmospheric simulations that are fully coupled from the meso to the micro scale and in which the only difference is the treatment of boundary layer physics at the gray zone domain. One simulation uses a well-established 5 parameterization, another uses its scale-aware version previously modified to accommodate gray zone resolutions, and a final one uses no parameterization at all and assumes that the gray zone domain can be run in large-eddy simulation (LES) mode.The simulated fields are cross-compared, and further compared to measurements collected during the Prince Edward Island Wind Energy Experiment. Use of LES in the gray zone domain influences the flow fields in a manner that is robust to temporal averaging. The best predictions of vertical wind shear were found for the simulations in which the gray zone is parameterized, 10 and the inclusion of a micro scale nest run in LES mode within the gray zone domains increased the model errors by producing overly homogeneous flow fields. The parameterized simulations also produced better agreement in terms of kinetic energy spectra at the two innermost simulation domains. In the gray zone domain, the energy decays as f −3 throughout most of the spectral range considered. In the micro scale domain, the same is only seen in the low-frequency end of the gray zone spectral range. In the high-frequency end, the energy decay follows a f −1 slope. Outside the gray zone spectral range, the micro scale 15 simulated spectra follow the expected f −5/3 slope and produce good agreement with measurements.

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Toward Numerical Modeling in the “Terra Incognita”

Cited by 570 publications

References 32 publications

A new k‐epsilon model consistent with Monin–Obukhov similarity theory

A new k‐epsilon model consistent with Monin–Obukhov similarity theory

Numerical simulation of pulsations in the bora wind

Analysis of Different Gray Zone Treatments in WRF-LES Real Case Simulations

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