環境系 725 号カテゴリー Ⅰ 日本建築学会環境系論文集第 81 巻第 725 号, ,2016 年 7 月 J. Environ. Eng., AIJ, Vol. 81 No. 725, , Jul., 2016 DOI

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1 カテゴリー Ⅰ 日本建築学会論文集第 81 巻第, ,2016 年 7 月 J. Environ. Eng., AIJ, Vol. 81 No. 725, , Jul., 2016 DOI 風速変動を考慮した自然換気通風性能評価手法の提案 LES(Large-Edd Simulation) による住宅の自然換気通風性状に関する研究その2 PROPOSAL OF AN EVALUATION METHOD FOR NATURAL CROSS-VENTILATION PERFORMANCE CONSIDERING FLOW FLUCTUATION Stud on naturall cross-ventilated house using large-edd simulation(les) part 2 有波裕貴 *, 赤林伸一 **, 富永禎秀 ***, 坂口淳 ****, 高野康夫 ***** ******, 本田美穂 Yuki ARINAMI, Shin-ichi AKABAYASHI, Yoshihide TOMINAGA, Jun SAKAGUCHI, Yasuo TAKANO and Miho HONDA The driving force ehind natural cross-ventilation is outdoor ind. The indoor airo distriution and o rate under cross-ventilation var greatl ecause the direction and velocit of ind changes constantl. Thus, cross-ventilation is said to e an unstead uid phenomena. Therefore, replicating actual uid phenomena using computational uid dnamics is ver important for evaluating the unstead cross-ventilation performances of houses. Recentl, unstead uid phenomena have een analzed using large-edd simulation. In this stud, a ne evaluation method that considers o uctuation for natural cross-ventilation is proposed. According to this method, particles are released at openings and the ratio of particles arriving at the evaluation area of a house model is calculated. The method sets inner half part over the central plane of the model as the evaluation area to eclude short circuit phenomena. Ratio of particles entering into the model, ratio of particles arriving at the evaluation area, effective ventilation rate and effective ventilation ratio are analzed for the simple house model. The evaluation results for the performance of this unstead natural cross-ventilation model are reported. Kewords : Computational Fluid Dnamics, Large-Edd Simulation(LES), Natural Cross-ventilation, Flow Fluctuation, Method of Cross Ventilation Performance, Particle tracking *1)~ 本論文は既発表文献で報告したものに加筆修正し, 再構成したものである * 新潟大学大学院自然科学研究科特任助教博士 ( 工学 ) Assist. Prof., Graduate School of Science and Technolog, Niigata Universit, Dr.Eng. ** 新潟大学大学院自然科学研究科教授工博 Prof., Graduate School of Science and Technolog, Niigata Universit, Dr.Eng. *** 新潟工科大学建築学科教授博士 ( 工学 ) Prof., Dept. of Architecture and Building Engineering, Niigata Institute of Technolog, Dr.Eng. **** 新潟県立大学国際地域学部国際地域学科教授博士 ( 工学 ) Prof., ISRD, Universit of Niigata Prefecture, Dr.Eng. ***** 菱機工業新潟支店博士 ( 工学 ) Roki Kogo Co., Ltd., Dr.Eng. ****** 鉄道建設運輸施設整備支援機構修士 ( 工学 ) ( 当時新潟大学大学院生 ) Japan Railwa Construction, Transport and Technolog Agenc, M.Eng. (Former Grad. Stud., Graduate School of Science and Technolog, Niigata Universit) 589

z Unit:[mm] SGS model Analsis region Size of house model Opening Area Boundar condition Analsis time t Minimum grid size Number of grids Inflow Out flow Wall Boundar Pre-analsis Main analsis Dnamic

0016[m 2 ] Instantaneous wind velocit components (u,v,w) are produced b driver region calculation (UZ 1/4, reference wind velocit =5.

2 z Unit:[mm] SGS model Analsis region Size of house model Opening Area Boundar condition Analsis time t Minimum grid size Number of grids Inflow Out flow Wall Boundar Pre-analsis Main analsis Dnamic Smagorinsk model =7.8, =1.8, z=1.8[m] =0.3, =0.3, z=0.3[m] [m 2 ] Instantaneous wind velocit components (u,v,w) are produced b driver region calculation (UZ 1/4, reference wind velocit =5.0[m/s], reference height=1000[mm]) Zero gradient Side,Top Free slip Ground Three laer model of Werner-Wengle wall Building wall functions 2.6[sec] 10.0[sec] [sec] 0.005[m] 210() 148() 117(z)3,636,360 Driver region 900 House model Wind Direction case House Model Positions of openings case1 Model A-1 the windward and leeward walls case2 Model A-2 the opposite walls parallel to the wind direction case3 Model B-1 the windward wall Driver region House model Wind Direction case4 Model B-2 the leeward wall case5 Model B-3 the wall parallel to the wind direction z Unit:[mm] 590

3 When evaluating the ventilation performance using pollutant removal efficienc (e.g. Purging Flow Rate), it is difficult to consider the influence of the short circuit with the case that the inflow and outflow openings are changing constantl. Pollutant Generating domain Pollutant Generating domain It is difficult to determine whether the particle is short circuit or not. Particle (Pollutant) Trajector of particles 591

4 Particle Trajector of particles Releasing points of particles Central plane of model area Count particles arriving at evaluation area. Particle Particle Trajector of particles Trajector of particles Releasing points of particles Particle Particle Trajector of particles Trajector of particles Count particles arriving at evaluation area. area Count particles entering into model. area Releasing points of particles Central plane of model Count particles arriving at evaluation area. Releasing points of particles Count particles entering into model. Central plane of model Count particles entering into model. Releasing points of particles Particle Particle Trajector of particles Trajector of particles area Releasing points of particles Count particles arriving at evaluation area. Particle Particle Trajector of particles Trajector of particles area Count particles arriving at evaluation area. Central plane of model area Releasing points of particles Central plane of model Count particles entering into model. Count particles entering into model. Releasing points of particles ii Releasing points of particles i Eclude particles eiting from model not arriving at evaluation area. 592

5 1 Setting of the analsis parameter. 1-1 Set the evaluation area (e.g., the inner half part of the house) to eclude short circuit phenomena. 1-2 Analze the spectrum of normal direction components of inlet and outlet wind velocit at openings of house model. 2 Release 100 particles in a frequenc of two times the peak frequenc calculated in Count particles entering into model as n in,i in Eq. (1). 3-2 Track and count particles arriving at evaluation area as n r,i in Eq. (1). 3-3 Compute the ratio of particles arriving at the evaluation area from Eq. (1). (1) 4-1 Calculate instantaneous inlet flow rate in the released time at openings as Q in,i in Eq. (2). 4-2 Compute the effective ventilation rate from Eq. (2). (2) 5 Compute the effective ventilation ratio from Eq. (3) based on the results of Case 1. (3) 593

6 594

7 595

8 : : : : : :case1 : [m 3 /h] i:(i1,2,3,n) 596

9 PROPOSAL OF AN EVALUATION METHOD FOR NATURAL CROSS-VENTILATION PERFORMANCE CONSIDERING FLOW FLUCTUATION Stud on naturall cross-ventilated house using large-edd simulation(les) part 2 Yuki ARINAMI *, Shin-ichi AKABAYASHI **, Yoshihide TOMINAGA ***, Jun SAKAGUCHI ****, Yasuo TAKANO ***** and Miho HONDA ****** * Assist. Prof., Graduate School of Science and Technolog, Niigata Universit, Dr.Eng. ** Prof., Graduate School of Science and Technolog, Niigata Universit, Dr.Eng. *** Prof., Dept. of Architecture and Building Engineering, Niigata Institute of Technolog, Dr.Eng. **** Prof., ISRD, Universit of Niigata Prefecture, Dr.Eng. ***** Roki Kogo Co., Ltd., Dr.Eng. ****** Japan Railwa Construction, Transport and Technolog Agenc, M.Eng. (Former Grad. Stud., Graduate School of Science and Technolog, Niigata Universit) INTRODUCTION niinimhnmnn,innhiiinini,iin,nnnn iinmininmi(),innihmhniniin is not observed using stead-state simulations (e.g., Ranolds-Averaged Navier-Stokes Simulation); nevertheless it is an actual phenomenon. In i,ininnhinin,nniinihinnnh Therefore, replicating actual phenomena using CFD is ver important to evaluate the unstead cross-ventilation performance of a house. Recentl, nihnmnhnninimin() In this stud, a new evaluation method for natural cross-ventilation that takes flow fluctuation into consideration is proposed. In this method, particles are released at openings and the ratio of particles arriving at the evaluation area within the house model is calculated. Ratio of particles ing into the model, ratio of particles arriving at the evaluation area, effective ventilation rate and effective ventilation ratio are analzed for the model. results concerning unstead natural cross-ventilation performance are reported. METHOD In this stud, particles are released based on the results of an LES analsis reported previousl. The evaluation area (i.e., the inner half part of the house) is set over the central plane of the model to eclude short circuit phenomena. The ratio of particles arriving at the evaluation area is 1imhninnhimhihin1ni stead state is achieved. Net, onl the particles that reached the evaluation area are counted as contributing to the natural cross-ventilation. The ratio of particles arriving at the evaluation area is computed from Equation (1) and the effective ventilation rate is computed from Equation (2) b hmninnhninnhiiiinhinin(3)hhiniini based on the results of Case 1 and the other cases. RESULTS AND DISCUSSION The results are as follows; (1) The ratio of particles arriving at the evaluation area in Cases 1, 2, 3, 4, and 5 are 97%, 42%, 58%, 49%, 57% on an average, respectivel. (2) The effective ventilation rates in Cases 1, 2, 3, 4, and 5 are m 3 /h, 0.98 m 3 /h, 1.76 m 3 /h, 1.20 m 3 /h, and 2.12 m 3 /h on average, respectivel. The effective ventilation ratio is given b Equation (3) based on the effective ventilation rate of Case 1. (3) In Cases 2, 3, 4, and 5 the average effective ventilation ratios are given b , , , and , respectivel. CONCLUSION nhi,ninmhnniinihniininhnnin nn,in2hinnniininim,hnniinhnmnn 2,hiniinnnim12hin1 The particle animation for this stud can be found at the URL below: (2015 年 12 月 10 日原稿受理,2016 年 4 月 7 日採用決定 ) 597

計画系 741 号カテゴリー Ⅱ 日本建築学会計画系論文集第 82 巻第 741 号, ,2017 年 11 月 J. Archit. Plann., AIJ, Vol. 82 No. 741, , Nov., 2017 DOI

計画系 741 号カテゴリー Ⅱ 日本建築学会計画系論文集第 82 巻第 741 号, ,2017 年 11 月 J. Archit. Plann., AIJ, Vol. 82 No. 741, , Nov., 2017 DOI カテゴリー Ⅱ 日本建築学会論文集第 82 巻第,297-2913,17 年 11 月 J. Archit. Plann., AIJ, Vol. 82 No. 741, 297-2913, Nov., 17 DOI http://doi.org/1.313/aija.82.297 住宅土地統計調査を用いた住宅残存率曲線の決定手法および既存住宅築年推定法の検討 DETERMINATION METHOD

環境系 725 号 カテゴリー Ⅰ 日本建築学会環境系論文集第 81 巻第 725 号, ,2016 年 7 月 J. Environ. Eng., AIJ, Vol. 81 No. 725, , Jul., 2016 DOI

環境系 725 号カテゴリー Ⅰ 日本建築学会環境系論文集第 81 巻第 725 号, ,2016 年 7 月 J. Environ. Eng., AIJ, Vol. 81 No. 725, , Jul., 2016 DOI