the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Introduction of a Trans-scale Numerical Simulation Framework Focusing on Urban Boundary Layer: WOCSS V1.0
Wei Li
Shuo Leng
Sunwei Li
Zhenzhong Hu
Pakwai Chan
Abstract. In the field of geoscience, the meso-scale tool to conduct weather forecast, which is also termed as Numerical Weather Prediction (NWP) package, is commonly used for simulating the urban boundary layer in the scale of 1 km~100 km. In the field of wind engineering, the Computational Fluid Dynamic (CFD) simulation tool is most popular for investigating the urban wind environment at the scale of 1 m~1 km. In the present study, a novel framework, named WOCSS with the version v1.0, combing the meso-scale NWP package of the Weather Research and Forecast (WRF) model and the micro-scale OpenFOAM code is introduced thanks to an open-source package of PreCICE. In detail, PreCICE realizes the trans-scale simulation of the urban wind environment through one-way nesting of porting the meso-scale simulation results to the boundaries of the micro-scale simulation. To this end, the adaptions made to the open-sourced codes of WRF and OpenFOAM are articulated, which fulfil the information exchanges between WRF and OpenFOAM via PreCICE library. A case study concerning the urban wind environment in a residential quarter in Shenzhen, China is conducted using WOCSS V1.0. The case study demonstrates that the proposed framework successfully presents the detailed wind environment inside the residential quarter under realistic meteorological condition.
Wei Li et al.
Status: open (until 21 Jun 2023)
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RC1: 'Comment on egusphere-2023-482', Anonymous Referee #1, 08 May 2023
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Please find attached for the detailed comments.
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RC2: 'Comments on egusphere-2023-482', Anonymous Referee #2, 15 May 2023
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Review comments for "Introduction of a Trans-scale Numerical SimulationFrameworkFocusing on Urban Boundary Layer: WOCSS V1.0"
Li et al
In this model description MS, the Authors describe the WOCSS framework for coupling for WRF and OpenFOAM for performing microscale simulation using mesoscale scale model data. The coupling is achieved through a one-way data exchange (from WRF to OpenFOAM) using the third-party package PreCICE. A preliminary simulation is performed, where the OpenFOAM results for are presented.Overall, the MS is very poorly prepared, both technically and rhetorically. An unproportionally large amount of text devoted to exposition, though I am willing to interpret this as a result of the Authors' lack of command in the English language, rather than a delibrate attempt distract and confuse the reader.
There is also a general lack of details regarding model description, test case preparation and discussion on preliminary results. Based on the information presented in the MS, I do not get the sense that the Authors have performed significant original work on this coupling framework to warrant a standalone publication. In addition, it is not intersting to reiterate OpenFOAM solver settings (viz. Table 2) without indicating which OpenFOAM solver is being used (I assume the default solver simpleFoam was used), or to show a mesh of the urban geometry (viz. Fig 5) without providing sufficient context on how the mesh is generated or the mesh statistics (i.e., how many cells, what type of cells, and mean/max/min cell size). Description of the parent mesoscale model is equally sparse, as with the configurations for the PreCICE coupling scheme. Further, showing that the OpenFOAM simulation can run for 120 seconds (Figs 6-8) at a qualitative level is far adequate. For instance, Chan and Butler (2021) and Piroozmand et al (2020) devised coupling frameworks for OpenFOAM, both capable of operating for at least a 24 hour period.
While reading Section 3.1 I have understood that the Authors used PreCICE to create a 3D field from the WRF model data, which is then prescribed into the OpenFOAM domain. This approach is incorrect, as this will cause spurious solution fields in the urban canopy region, in addition of not being mass or energy conservative. An acceptable approach is to map the WRF variable fields as lateral boundary conditions for the OpenFOAM domain, which allows the solution field inside the OpenFOAM domain to develop in its own accord. Of course, this is technically much more challenging, as pointed out by Sprague and Satkauskas (2015), but has been successfully demonstrated in Jeanjean et al (2015), as well as in the two aforementioned works.
In its current form, I strongly believe that this MS is far from meeting the technical and rhetorical standards for further consideration with this journal, nor have the Authors demonstrated feasilibility of the present modelling framework at a adequate level precedented in comparable works. I therefore recommend this MS be rejected. In the meantime, the Authors are urged to critically and carefully review the purpose and approach they take in the context of this MS.
References:
- EC Chan, TM Butler (2021) GMD 14, 4555–4572.
- APR Jeanjean et al (2015) Atmos Environ 120, 1-14.
- P Piroozmand et al (2020) J Wind Eng Ind Aerodyn 197, 104059.
- MA Sprague, I Satkauskas (2015) Comput Fluids 115, 75-85.
Citation: https://doi.org/10.5194/egusphere-2023-482-RC2
Wei Li et al.
Model code and software
WOCCS-v1.0 W. Li, S. Leng, S. Li, and Z. Hu https://gitee.com/skywall/meso-micro-simulation/tree/master
Wei Li et al.
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