{"title":"Comprehensive windproof effects evaluation of low-coverage meadow paving layout forms based on numerical wind tunnel experiments","authors":"Zhijun Wang , Kaihe Zhang","doi":"10.1016/j.ecoleng.2024.107464","DOIUrl":null,"url":null,"abstract":"<div><div>The sustainability of the ecological system in Alpine regions is being increasingly threatened by grassland desertification under climate change conditions. In order to address this global issue, this study took the typical desertified grassland in the northeastern edge of the Tibetan Plateau, as a case, proposing a low-coverage meadow paving layout forms for mitigating wind and sand erosion. Six paving layout forms (“spacing strips” (SS-1, SS-1.5), “lattice-shaped” (LS-1, LS-2), checkerboard intervals“ (CI), “square intervals” (SI)) were designed and comprehensive analysis of their windproof effects were explored by numerical wind tunnel experiments. The patchy meadow is generalized as a porous medium and the porosity source terms were added to the RNG <em>k-ε</em> turbulence model to simulate the disturbance of the meadow on the airflow characteristics. The improved mathematical model was verified by the field experiments of <span><span>Hesp et al. (2019)</span></span>. Following that, a series of numerical wind tunnel experiments were conducted on the 6 arrays, with the single meadow coverage of 40.00 %, at incoming wind speeds of 7 m/s (low), 11 m/s (medium) and 15 m/s (high) (wind speed is 2 m from the surface). In addition, this study uses flow field, windproof efficiency (E), downwind speed percentage (DSP), integrated cumulative distribution function of wind speeds below the threshold of 4.19 m/s in Maqu (<em>P</em> < 4.19 m/s) and economy to comprehensively evaluate the windproof effects based on the results of numerical wind tunnel experiments. Evaluation results based on individual index indicated that: (1) The meadow array significantly reduces the wind speed, and the meadow array pattern changes the airflow field around the meadow. (2) The E value in windproof areas for different meadow layouts ranking from largest to smallest is as follows: LS-1 > SS-1 > CI > SS-1.5 > LS-2 > SI. (3) Within the windproof area, the DSP of various meadow arrays revealed significant distribution differences, with significant reduction occurring especially for SS-1, SS-1.5, and LS. (4) As for the value of <em>P</em><sub><4.19 m/s</sub>, the order from largest to smallest for the 6 layouts reveals a law of LS-1 > SS-1 > SS-1.5 > CI > LS-2 > SI. (5) The paving decrement compared to the full pavement ranking from largest to smallest is SS-1.5 > CI > SS-1 > SI > LS-2 > LS-1. Based on the comprehensive evaluation results, which consider ecological economic benefits, it can be concluded that SS-1 demonstrates superior effectiveness as a low-coverage wind and sand control mode for a single wind direction. On the other hand, LS is found to be more suitable for scenarios involving multiple wind directions or variable wind directions. The anticipated outcomes of this study are poised to offer a novel approach for managing wind and sand, as well as facilitating ecological restoration in the alpine desertified grassland in the future.</div></div>","PeriodicalId":11490,"journal":{"name":"Ecological Engineering","volume":"211 ","pages":"Article 107464"},"PeriodicalIF":3.9000,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Ecological Engineering","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0925857424002891","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The sustainability of the ecological system in Alpine regions is being increasingly threatened by grassland desertification under climate change conditions. In order to address this global issue, this study took the typical desertified grassland in the northeastern edge of the Tibetan Plateau, as a case, proposing a low-coverage meadow paving layout forms for mitigating wind and sand erosion. Six paving layout forms (“spacing strips” (SS-1, SS-1.5), “lattice-shaped” (LS-1, LS-2), checkerboard intervals“ (CI), “square intervals” (SI)) were designed and comprehensive analysis of their windproof effects were explored by numerical wind tunnel experiments. The patchy meadow is generalized as a porous medium and the porosity source terms were added to the RNG k-ε turbulence model to simulate the disturbance of the meadow on the airflow characteristics. The improved mathematical model was verified by the field experiments of Hesp et al. (2019). Following that, a series of numerical wind tunnel experiments were conducted on the 6 arrays, with the single meadow coverage of 40.00 %, at incoming wind speeds of 7 m/s (low), 11 m/s (medium) and 15 m/s (high) (wind speed is 2 m from the surface). In addition, this study uses flow field, windproof efficiency (E), downwind speed percentage (DSP), integrated cumulative distribution function of wind speeds below the threshold of 4.19 m/s in Maqu (P < 4.19 m/s) and economy to comprehensively evaluate the windproof effects based on the results of numerical wind tunnel experiments. Evaluation results based on individual index indicated that: (1) The meadow array significantly reduces the wind speed, and the meadow array pattern changes the airflow field around the meadow. (2) The E value in windproof areas for different meadow layouts ranking from largest to smallest is as follows: LS-1 > SS-1 > CI > SS-1.5 > LS-2 > SI. (3) Within the windproof area, the DSP of various meadow arrays revealed significant distribution differences, with significant reduction occurring especially for SS-1, SS-1.5, and LS. (4) As for the value of P<4.19 m/s, the order from largest to smallest for the 6 layouts reveals a law of LS-1 > SS-1 > SS-1.5 > CI > LS-2 > SI. (5) The paving decrement compared to the full pavement ranking from largest to smallest is SS-1.5 > CI > SS-1 > SI > LS-2 > LS-1. Based on the comprehensive evaluation results, which consider ecological economic benefits, it can be concluded that SS-1 demonstrates superior effectiveness as a low-coverage wind and sand control mode for a single wind direction. On the other hand, LS is found to be more suitable for scenarios involving multiple wind directions or variable wind directions. The anticipated outcomes of this study are poised to offer a novel approach for managing wind and sand, as well as facilitating ecological restoration in the alpine desertified grassland in the future.
期刊介绍:
Ecological engineering has been defined as the design of ecosystems for the mutual benefit of humans and nature. The journal is meant for ecologists who, because of their research interests or occupation, are involved in designing, monitoring, or restoring ecosystems, and can serve as a bridge between ecologists and engineers.
Specific topics covered in the journal include: habitat reconstruction; ecotechnology; synthetic ecology; bioengineering; restoration ecology; ecology conservation; ecosystem rehabilitation; stream and river restoration; reclamation ecology; non-renewable resource conservation. Descriptions of specific applications of ecological engineering are acceptable only when situated within context of adding novelty to current research and emphasizing ecosystem restoration. We do not accept purely descriptive reports on ecosystem structures (such as vegetation surveys), purely physical assessment of materials that can be used for ecological restoration, small-model studies carried out in the laboratory or greenhouse with artificial (waste)water or crop studies, or case studies on conventional wastewater treatment and eutrophication that do not offer an ecosystem restoration approach within the paper.