| 1. |
＃Kotaro Kitamura, ＠Takanori Uchida, Tessei Miwa, ASSESSMENT OF THE WAKE IMPACT ON FLOATING WIND TURBINES, The 33rd International Symposium on Transport Phenomena, 2023.09. |
| 2. |
Koichiro Shibuya, Takanori Uchida, WIND TUNNEL EXPERIMENTS AND LES TO REVEAL ASYMMETRY IN YAWED WIND TURBINE WAKE FLOW, The 33rd International Symposium on Transport Phenomena, 2023.09. |
| 3. |
＃Koichiro Shibuya, Takanori Uchida
, Wake asymmetry of yaw state wind turbines, ASME-JSME-KSME Joint Fluids Engineering Conference, 2023.07. |
| 4. |
＠Takanori Uchida, Numerical visualization of wind turbine wakes using passive scalar advection-diffusion equation and its application to wake management Theme, Theme 02: Wind farm-level modelling and analysis, Wind Energy Science Conference 2023, 2023.05. |
| 5. |
Takanori Uchida, Practical Applications of Supercomputer Simulations of Airflows past Wind Turbines/Farms, Join Workshop on Offshore Wind Energy for Coming collaboration between Germany and Japan, 2020.03. |
| 6. |
Yuki Fukatani, Takanori Uchida, Yoshihiro Taniyama, Development of a New Wake Model by Validating with Results of On-Site Wind Resource Measurement, The 2nd Pacific Rim Thermal Enginerring Concerence, 2019.12. |
| 7. |
Takanori Uchida, Large-Eddy Simulation of Wind-Turbine Wakes under Various Atmospheric Stability Conditions, The 2nd Pacific Rim Thermal Engineering Concerence, 2019.12. |
| 8. |
Takanori Uchida, Micro-siting Technique for Wind Turbine Generator by Using Large-Eddy Simulation, International Workshop on Environmental Engineering 2019(IWEE2019), 2019.06. |
| 9. |
Taiga Murakami, Takanori Uchida, Yuji Ohya, Koichi Watanabe, Research on the efficiency improvement of wind turbines with brim diffuser for staggered arrangement, 第10回九大－KAISTシンポジウム, 2018.12. |
| 10. |
Taiga Murakami, Takanori Uchida, Yuji Ohya, Koichi Watanabe, Research on the efficiency improvement of wind turbines with brim diffuser for staggered arrangement, 第10回九大－KAISTシンポジウム, 2018.12. |
| 11. |
Kenji Ono, Takanori Uchida, High-Throughput Parallel Simulation of Airflow for Detailed Land Configuration, Asian Computational Fluid Dynamics Conference (ACFD), 2018.10. |
| 12. |
Kenji Ono, Takanori Uchida, Two-Stage in Situ Parallel Meshing for Large-Scale Atmospheric Fluid Simulation Over Complex Topography, 2018.10. |
| 13. |
Yoshihiro TANIYAMA, Takanori UCHIDA, Keiji MATSUSHIMA, Asako INOMATA, Yuki FUKATANI, Michiko NAKANO, Toshiki OSAKO, Development of Quantitative Evaluation Method of Wake Loss Using Mockup Model of Real Wind Turbine, Grand Renewable Energy 2018, 2018.06. |
| 14. |
Yasushi KAWASHIMA, Takanori UCHIDA, Soichiro KIYOKI, Katsutoshi KONDO, A Study on the Effects of Terrain-induced Turbulence on Wind Turbine Blade Fatigue Loads, Grand Renewable Energy 2018, 2018.06. |
| 15. |
Akiyoshi Iida, Takanori Uchida, Hiroshi Imamura, Yuko Ueda, Shinobu Yoshimura, Introduction of Post K Application Development for Wind Farm Modeling, IEA Wind Task31 Symposium, 2018.04. |
| 16. |
Yoshinobu Yamade, Takanori Uchida, Chisachi Kato, Akiyoshi Iida, Yasumasa Suzuki, Shinobu Yoshimura, Hiroshi Imamura, Yuko Ueda, HidetoYoshimura, Large Eddy Simulation of Flow around Wind Turbine and in Wind Farm, IEA Wind Task31 Symposium, 2018.04. |
| 17. |
Shintaro Kawahara, Takanori Uchida, Koichi Watanabe, Yuji Ohya, Improvement of Power Generation Performance of a New Type of Solar Tower, The 9th Kyushu University-KAIST Symposium on Aerospace Engineering, 2017.12. |
| 18. |
E. Takahashi1, K. Onishi1, H. Tanigawa, T. Uchida, K. Sugitani, K. Hirata, Experiment and Computation on Aerodynamic Characteristics and Flow Visualisation of Basic Airfoils at Very-Low Reynolds Numbers, The 11th Pacific Symposium on Flow Visualozation and Image Processing, 2017.12, The airfoil is one of the most elemental devices for flying/swimming robots to control flow and its reacting force, which determines their basic performances. However, the aerodynamic characteristics of the airfoil have been researched mainly in high Reynolds-number ranges more than 106, in a historic context closely related with the developments of airplanes and fluid machineries in the last century^([1], [2]).
On the other hand, we have been requiring more precise knowledge about the aerodynamic characteristics of the airfoil especially in low Reynolds-number ranges less than 106, because of the recent miniaturization of robots such as unmanned aerial vehicles known as UAVs or micro air vehicles known as MAVs, in addition to the importance of insect/bird flight dynamics, small-scale machines like micro fluid machineries and micro combustion engines and so on.
In the present study we investigate the relationship between various aerodynamic characteristics and attack angle α for flat plate NACA0015 and iNACA0015 (the NACA0015 placed back to front) by numerical analysis and water tank experiment at Re = 1.0102 8.0102. Then, we investigate the effects of attack angle α upon various aerodynamic characteristics such as the lift coefficient CL, drag coefficient CD and the lift-to-drag ratio CL/CD. In order to discuss the revealed α effects, we visualise the flow around the airfoils using the Q value, the helicity, streamlines distributions around the airfoils at α = 0 – 24 deg., together with PIV analysis based on water tank experiment..  |
| 19. |
Keiko Udo, Tsukasa Kuribayashi, Takanori Uchida, Characteristics of Wind Field over an Artificial Straight Dune, Coastal Dynamics 2017, 2017.06. |
| 20. |
Akiyoshi Iida, Takanori Uchida, Hiroshi Imamura, Yuko Ueda, Shinobu Yoshimura, Introduction of Post K Application Development for Wind Farm Modeling, IEA Task 31 Wakebench Phase 2: 2nd Annual meeting, 2017.05. |
| 21. |
Akio Munakata, Jumpei Miyazaki, Uli Goeltenbott1 Yuji Ohya, Takanori Uchida, Multi Rotor System using Diffuser Augmented Wind Turbines for Power Increase, The 15th World Wind Energy Conference (WWEC2016), 2016.11. |
| 22. |
Shigeo Yoshida, Takanori Uchida, Omar Ibrahim, Yasushi Kawashima, Site Specific Evaluation Methods by Aero-Elastic Wind Turbine and LES Time Variant Wind Models, The 15th World Wind Energy Conference (WWEC2016), 2016.11. |
| 23. |
Soichiro Kiyoki, Takanori Uchida, Yasushi Kawashima, Katsutoshi Kondo, Impact Assessment of Terrain Turbulece to Wind Turbine Fatigue, The 15th World Wind Energy Conference (WWEC2016), 2016.11. |
| 24. |
Achmad Rachmad Tullah Tjan, Yuji Ohya, Takashi Karasudani, Takanori Uchida, Development of a Floating Body for an Airborne Wind Energy System, The 8th KAIST-Kyushu University Symposium on Aerospace Engineering, 2016.10. |
| 25. |
Masahiro Konishi, Shigeyuki Sako, Takanori Uchida, Ryou Araya, Koui Kim, Yuzuru Yoshii, Mamoru Doi, Kotaro Kohno, Takashi Miyata, Kentaro Motohara, Masuo Tanaka, Takeo Minezaki, Tomoki Morokuma, Yoichi Tamura, Toshihiko Tanabé, Natsuko Kato, Takafumi Kamizuka, Hidenori Takahashi, Tsutomu Aoki, Takao Soyano, Ken'ichi Tarusawaf, The university of Tokyo atacama observatory 6.5m telescope Enclosure design and wind analysis, Ground-Based and Airborne Telescopes VI, 2016.01, We present results on the computational uid dynamics (CFD) numerical simulations as well as the wind tunnel experiments for the observation facilities of the University of Tokyo Atacama Observatory 6.5m Telescope being constructed at the summit of Co. Chajnantor in northern Chile. Main purpose of this study starting with the baseline design reported in 2014 is to analyze topographic effect on the wind behavior, and to evaluate the wind pressure, the air turbulence, and the air change (ventilation) efficiency in the enclosure. The wind velocity is found to be accelerated by a factor of ∼ 1.2 to reach the summit (78 m sec-1 expected at a maximum), and the resulting wind pressure (3,750 N m-2) is used for the framework design of the facilities. The CFD data reveals that the open space below the oor of the facilities works efficiently to drift away the air turbulence near the ground level which could significantly affect the dome seeing. From comparisons of the wind velocity field obtained from the CFD simulation for three configurations of the ventilation windows, we dind that the windows at a level of the telescope secondary mirror have less efficiency of the air change than those at lower levels. Considering the construction and maintenance costs, and operation procedures, we finally decide to allocate 13 windows at a level of the observing oor, 12 at a level of the primary mirror, and 2 at the level of the secondary mirror. The opening area by those windows accounts for about 14% of the total interior surface of the enclosure. Typical air change rate of 20{30 per hour is expected at the wind velocity of 1 m sec-1.. |
| 26. |
Hirohito Ohto, Takanori Uchida, Yoshihiro Taniyama, Toshiki Osako, Airflow Evaluation of Wind Farm Site over Complex Terrain Using LES Turbulence Model, International Conference on Power Engineering, ICOPE 2015, 2015.12, Recently, the new wind farm has been successfully built in Nagashima island, Kagoshima prefecture. This site is located in complex terrain and, the flow above the ground is also thought to be complex. We analyzed the flow here using the RIAM-COMPACT (Uchida 2014) natural terrain version software, which is based on an LES turbulence model. The accuracy of this software was proved in previous studies. In addition to the CFD analysis, we also conducted airflow measurements using hot wire technique in the boundary layer wind tunnel of the Research Institute for Applied Mechanics, Kyushu University. In this experiment, the vertical wind velocity profile were obtained at 3 locations as time step data, from which we calculated turbulence. The value of scalar wind speed and turbulence by CFD and experiment generally has same tendency at each height of each location. These agreements demonstrates the validity of this CFD software based on LES turbulence modeling.. |
| 27. |
Masaki Wataka, Yuji Ohya, Takashi Karasudani, Takanori Uchida, Improvement of Power Generation of the Wind Solar Tower, International Conference on Power Engineering, ICOPE 2015, 2015.12, In 1989, a pilot plant of a solar chimney was erected in Manzanares Spain to evaluate the feasibility of the solar tower as a new source of renewable energies. Since then, the solar tower was discussed in the press, but no commercial plant succeeded the research. A reason for this could be the relative low power output compared with other renewable energy production systems. However, the power generation system of a wind solar tower can be designed and constructed at relatively low cost. A solar tower consists mainly of three components. The collector area is a glass roof, above ground with increasing height towards the center. Attached to the center of the collector is a vertical tower inside which a wind turbine is mounted at the lower entry into the tower. When solar radiation heats the ground through the glass roof, the uprising warm air is guided to the center into the tunnel. A wind solar tower that can generate electricity in a simple structure, and enables easy and less costly maintenance, has considerable advantages. Since the solar tower reaches several hundreds of meters into the sky, the tower exit is at a level of higher wind speeds compared to the ground. If wind passes over the tower exit, it can induce air flow inside the tower. Hence, the solar tower could be capable of producing electricity at night when the solar radiation is not available. In our research we are aiming to improve the overall performance of the solar tower focusing on the tower component. We consider airflow caused by thermal updraft and air flow in the tower induced by wind flowing over the tower exit at the top. We conclude that the shape of the tower has a significant effect on the performance of the solar tower. Therefore, our future research will focus on further optimization of the shape of the tower.. |
| 28. |
Shoichi Tanaka, Yoshihiro Taniyama, Asako Inomata, Yutaka Hashiba, Takanori Uchida, Wind Resource Evaluation for Optimizing Wind Turbine Placement on Complex Terrain, International Conference on Power Engineering, ICOPE 2015, 2015.12, As the wind farms are constructed in complex terrain in recent years, the wind resource analysis is becoming more important. The purpose of our study is optimizing wind turbine placement in complex terrain for more AEP. In this paper we performed validation of CFD wind analysis. The validation method is comparison of measured and calculated wind profiles. The wind speed and direction were measured by "WINDCUBE" at the altitude from 40m to 260m by 20m for about one month in Nagashima-Kuronoseto wind farm in Nagashima island, Kagoshima prefecture. "RIAM-COMPACT", which is a CFD software based on an LES turbulence model, was used for wind flow analysis. We compared the 10min averaged data by measurement and all time averaged data by CFD on the wind profiles of speed, direction, and standard deviation of north-west and north-east winds.. It is confirmed that the CFD results reproduce the difference of topographic effects depending on wind direction and that "RIAM-COMPACT" is able to predict the actual wind affected by complex terrain.. |
| 29. |
Jumpei Miyazaki, Uli Goeltenbott, Yuji Ohya, Takashi Karasudani, Takanori Uchida, Study for the Implementation of Clustered Wind Lens Turbines, 2015 7th Kyushu University-KAIST Symposium on Aerospace Engineering,, 2015.12. |
| 30. |
Hirohito Ohto, Takanori Uchida, Yoshihiro Taniyama, Toshiki Osako, Airflow Evaluation of Wind Farm Site Over Complex Terrain Using LES Turbulence Model, The 13th Asian International Conference on Fluid Machinery, 2015.09, Recently, the new wind farm has been successfully built in Nagashima island, Kagoshima prefecture. This site is located in complex terrain and, the flow above the ground is also thought to be complex. We analyzed the flow here using the RIAM-COMPACT (Uchida 2014) natural terrain version software, which is based on an LES turbulence model. The accuracy of this software was proved in previous studies. In addition to the CFD analysis, we also conducted airflow measurements using hot wire technique in the boundary layer wind tunnel of the Research Institute for Applied Mechanics, Kyushu University. In this experiment, the vertical wind velocity profile were obtained at 3 locations as time step data, from which we calculated turbulence. The value of scalar wind speed and turbulence by CFD and experiment generally has same tendency at each height of each location. These agreements demonstrates the validity of this CFD software based on LES turbulence modeling.. |
| 31. |
Takanori Uchida, Yuji Ohya, High resolution LES of turbulent airflow over complex terrain, 7th Asia-Pacific Conference on Wind Engineering, APCWE-VII, 2009.12, It is highly important in Japan to choose a good site for wind turbines, because the spatial distribution of wind speed is quite complicated over steep complex terrain. We are developing the unsteady numerical model called the RIAM-COMPACT (Research Institute for Applied Mechanics, Kyushu University, Computational Prediction of Airflow over Complex Terrain). The RIAM-COMPACT is based on the LES (Large-Eddy Simulation). The object domain of the RIAM-COMPACT is from several m to several km. First, to test the accuracy of the RIAM-COMPACT we have performed the experimental and numerical simulation of a non-stratified airflow past a two-dimensional ridge and a three-dimensional hill in a uniform flow. Attention is focused on airflow characteristics in a wake region. For this purpose, the velocity components were measured with a SFP (Split-Film Probe) in the wind tunnel experiment. Through comparison of the experimental and numerical results, they showed a good agreement. The accuracy of both of the wind tunnel experiment by the SFP and also numerical simulation by the RIAM-COMPACT were confirmed. Next, we have applied the RIAM-COMPACT to the airflow over real complex terrain. The numerical results obtained by RIAM-COMPACT demonstrated that the changes induced on the wind field by the topographic effect, such as the local wind acceleration and the flow separation, were successfully simulated. The amount of power generation was evaluated in consideration of the correlation with the observational data. Finally, wind simulation of an actual wind farm was executed using the high resolution elevation data. As a result, an appropriate point and an inappropriate point for locating a wind turbine generator were shown based on the numerical results obtained. This cause was found to be a topographical irregularity in front of the wind turbine generator.. |
| 32. |
Yuji Ohya, Reina Nakamura, Takanori Uchida, Intermittent bursting of turbulence in a stable boundary layer with low-level jet, 17th Symposium on Boundary Layers and Turbulence, 27th Conference on Agricultural and Forest Meteorology, 17th Conference on Biometeorology and Aerobiology, 2006.12. |
| 33. |
Toshiyuki Sanada, Masatoshi Fujino, Daisuke Matsushita, Takanori Uchida, Hikaru Matsumiya, Masao Watanabe, Yoshinori Hara, Minori Shirota, Numerical site calibration on a complex terrain and its application for wind turbine performance measurements, European Wind Energy Conference and Exhibition 2006, EWEC 2006, 2006.12, A numerical site calibration, which employs CFD (Computational Fluid Dynamics) for wind field simulation over a complex terrain to evaluate flow distortion factors, applied to the actual wind turbine site on a complex terrain that fails to satisfy the IEC standard is proposed. Unlike the conventional numerical site calibration, proposed one provides not only flow distortion factors evaluated from wind speeds obtained on both wind turbine and any observation points on a terrain, but also the preferable wind direction for wind turbine performance measurements, owing to highly accurate CFD method combined with both large eddy simulation and geographical information system. Wind field data obtained by meteorological mast is corrected by the calculated distortion factors to the wind speed on wind turbine. This predicted wind speed is investigated by comparing with the wind turbine performance data on a actual site. Further the possibility of the proposed wind turbine performance measurements is discussed.. |
