1:45 PM - 3:15 PM
[O11-P101] Verifying Wind Holes’ Effectiveness of Tower Block
Keywords:Urban Environment, Wind Holes, Wind tunnel testing
1, Research Background & Objectives
Wind holes to control building winds. Installing one in bulk is more effective than in multiple locations (Yoshida,1990). There are few detailed analyses and some Installations disadvantage. So, the objectives are to verify effective wind hole location, explore ways to utilize wind through wind hole, and consider the practicality of wind hole by comparing its advantages and disadvantages.
2, Experiment
Verify whether the model reproduces the building wind
The typical features of building wind: (a) Wind on the side of a building flows hard
(b) Downward flow occurs
The following experiments were conducted to verify these two features.
(a)Wind speed measurement experiment (fig. 1)
The distance between the model and the fan was set at 1.5 m. A total of 60 data acquisitions of wind velocity on the side of the model were performed for 1 minute, 1 second each, 5 times each with and without the model.
(b) Visualization experiment (fig. 2)
Set some flags with red mark on the face of the model and wind flowed through for 1 minutes to capture the appearance.
Verify the difference in effect depending on the location of wind holes
The same measurements as in Experiment 1(a) are made at different wind hole locations.
1 Five wind holes (width: 15 cm, height: 5 cm) were placed in the model, and the same measurements as in Experiment I (a) were made at different positions of the wind holes (Fig. 4).
2 The same measurements were made for the wind holes that were considered to be highly effective in 1, but at different measurement positions. In addition to the side of the model, two new measurement positions were added: in front of the model and behind the model (Fig. 5).
3, Results and Discussion
The table 1 shows the average wind speeds per time. It was found that the presence of the model increased the wind speed at the side of the building.
Figure 6 shows the actual flag. The results suggest that the wind flow is as shown by the green arrows in the figure. From the analysis results, it is estimated that the wind hitting the front of the model was split into upper and lower winds in the bottom two-thirds of the model. This result is highly reliable, since the wind blowing on the front of a building tends to split vertically at the position two-thirds from the bottom of the building (Wind Engineering Institute, Inc., 1989).
The results of (a) and (b) indicate that the model can reproduce the building wind.
Fig. 7-9 show the “average wind speed difference = (wind speed with wind holes) - (wind speed without wind holes)”; the smaller the value, the more effective the wind holes are.
1 The measurement in the side of the building
Upper Wind holes
No effect was observed. This may be because the wind blowing above two-thirds of the building does not flow to the sides of the building based on the results of Experiment I(b).
Bottom three wind holes
Based on the fact that all wind holes were able to reduce the wind at the side of the building and the results of Experiment 1(b), it can be assumed that the downward flow passes through the wind holes. However, the variation in the effect of the three wind holes is greater than that of the top two wind holes. This is thought to be because the effect of the lower three wind holes is directly affected by the changes in the downward flow due to errors in the position and angle of the fan and environmental factors.
2 Measurement at multiple locations
The measurements in front of the model (Fig. 8) showed that the winds from the building were reduced at all wind holes. On the other hand, the measurement at the back of the model (Fig. 9) shows that wind is generated at the back of the building when any of the wind holes are drilled. The wind blowing behind the model was strongest when the lowest wind hole was placed. This wind is thought to be generated because the wind through the wind hole blows directly to the back of the model, and the wind blowing behind the model is stronger when the wind hole is placed closer to the ground.
4, Conclusion and prospects
Wind holes are thought to reduce building winds that affect people on the ground. However, small errors in the way the wind blows can make a difference in the effectiveness of wind holes. In addition, because the location of the wind hole will cause new wind to blow behind the building, it is necessary to consider the optimal location of the wind hole in consideration of the environment surrounding the building when installing the wind hole.
In the future, we will study the structure of wind holes that can utilize the wind that passes through the wind holes by increasing the wind collection effect while maintaining the building wind effect.
Wind holes to control building winds. Installing one in bulk is more effective than in multiple locations (Yoshida,1990). There are few detailed analyses and some Installations disadvantage. So, the objectives are to verify effective wind hole location, explore ways to utilize wind through wind hole, and consider the practicality of wind hole by comparing its advantages and disadvantages.
2, Experiment
Verify whether the model reproduces the building wind
The typical features of building wind: (a) Wind on the side of a building flows hard
(b) Downward flow occurs
The following experiments were conducted to verify these two features.
(a)Wind speed measurement experiment (fig. 1)
The distance between the model and the fan was set at 1.5 m. A total of 60 data acquisitions of wind velocity on the side of the model were performed for 1 minute, 1 second each, 5 times each with and without the model.
(b) Visualization experiment (fig. 2)
Set some flags with red mark on the face of the model and wind flowed through for 1 minutes to capture the appearance.
Verify the difference in effect depending on the location of wind holes
The same measurements as in Experiment 1(a) are made at different wind hole locations.
1 Five wind holes (width: 15 cm, height: 5 cm) were placed in the model, and the same measurements as in Experiment I (a) were made at different positions of the wind holes (Fig. 4).
2 The same measurements were made for the wind holes that were considered to be highly effective in 1, but at different measurement positions. In addition to the side of the model, two new measurement positions were added: in front of the model and behind the model (Fig. 5).
3, Results and Discussion
The table 1 shows the average wind speeds per time. It was found that the presence of the model increased the wind speed at the side of the building.
Figure 6 shows the actual flag. The results suggest that the wind flow is as shown by the green arrows in the figure. From the analysis results, it is estimated that the wind hitting the front of the model was split into upper and lower winds in the bottom two-thirds of the model. This result is highly reliable, since the wind blowing on the front of a building tends to split vertically at the position two-thirds from the bottom of the building (Wind Engineering Institute, Inc., 1989).
The results of (a) and (b) indicate that the model can reproduce the building wind.
Fig. 7-9 show the “average wind speed difference = (wind speed with wind holes) - (wind speed without wind holes)”; the smaller the value, the more effective the wind holes are.
1 The measurement in the side of the building
Upper Wind holes
No effect was observed. This may be because the wind blowing above two-thirds of the building does not flow to the sides of the building based on the results of Experiment I(b).
Bottom three wind holes
Based on the fact that all wind holes were able to reduce the wind at the side of the building and the results of Experiment 1(b), it can be assumed that the downward flow passes through the wind holes. However, the variation in the effect of the three wind holes is greater than that of the top two wind holes. This is thought to be because the effect of the lower three wind holes is directly affected by the changes in the downward flow due to errors in the position and angle of the fan and environmental factors.
2 Measurement at multiple locations
The measurements in front of the model (Fig. 8) showed that the winds from the building were reduced at all wind holes. On the other hand, the measurement at the back of the model (Fig. 9) shows that wind is generated at the back of the building when any of the wind holes are drilled. The wind blowing behind the model was strongest when the lowest wind hole was placed. This wind is thought to be generated because the wind through the wind hole blows directly to the back of the model, and the wind blowing behind the model is stronger when the wind hole is placed closer to the ground.
4, Conclusion and prospects
Wind holes are thought to reduce building winds that affect people on the ground. However, small errors in the way the wind blows can make a difference in the effectiveness of wind holes. In addition, because the location of the wind hole will cause new wind to blow behind the building, it is necessary to consider the optimal location of the wind hole in consideration of the environment surrounding the building when installing the wind hole.
In the future, we will study the structure of wind holes that can utilize the wind that passes through the wind holes by increasing the wind collection effect while maintaining the building wind effect.