Experimental study of tsunami wave load acting on storage tank in coastal area Graduate School of Engineering, Osaka University Wataru Kunimatsu Graduate School of Engineering, Osaka University Shinji Nishiyama Graduate School of Engineering, Osaka University Tomohiro Furuse Graduate School of Engineering, Osaka University Shin-ichi Aoki Graduate School of Engineering, Osaka University Susumu Araki Naruo Technical Research Institute, Toyo Construction Co Yasuo Kotake 1
Outline 1. Introduction 2. Experimental set-up 3. Experimental results 3.1 The horizontal component of the tsunami wave load 3.2 The vertical component of the tsunami wave load 3.3 Comparison without and with the surrounding tanks 3.4 Characteristic of impulsive force on a tank 4. Conclusion 2016/1/13 2
1.Introduction
Introduction Energy resource like petroleum or highly pressurized gas are stored in cylindrical tanks or spherical tanks Industrial parks near coastal area The characteristics of the damage in Tohoku earthquake mainly storage tanks were damaged the damage to their parks was spread all over the parks by the tsunami 2016/1/13 4
Introduction For the Nankai trough earthquake Damage to industrial parks will lead to damage to the hinterland So, we need to estimate the tsunami wave load acting on storage tanks accurately take countermeasures against tsunami striking But research on industrial parks at coastal area hasn t been done enough So we have to investigate these matters not only fundamentally but also practically 2016/1/13 5
Introduction Point at issue of estimating forces it is difficult to estimate tsunami wave load acting on a storage tank from a tsunami height in front of harbors Purpose we investigate The fluid motion in a harbor using a wave basin in which cross-shore and longshore fluid motion is generated The applicability of conventional formula to estimating tsunami wave load acting on a storage tank 2016/1/13 6
2.Experimental set-up
Experimental set-up Wave basin Model scale is 1/100 Storage site Breakwater Offshore measurement point Seabed slope gradient 1/10 Tsunami generator Toyo Construction Co.,LTD. Naruo Technical Research Institute Wave basin with the tsunami generator(30m 19m) 2016/1/13 8
Experimental set-up The storage site : Measurement point of tsunami wave load The circular cylinder diameter 15cm/height 10cm Without the surrounding tanks With the surrounding tanks 2016/1/13 9
water level(cm) Experimental set-up The tsunami wave generation the offshore water surface elevation Maximum water surface elevation at the offshore point Wave generator stroke Case-1 6.9cm 140cm/15s Case-2 9.7cm 140cm/10s Case-3 repeating Case-2 three times The piston motion of the wave generator (cm) water level(cm) water level(cm) Case-1 Case-2 Case-3 2016/1/13 10
Experimental set-up Experimental procedure We measured 1 inundation depth and velocity at all points without any tank or oil wall which surrounds the storage site 2 inundation depth, velocity and tsunami wave load acting on a tank at each of 8 red points without surrounding tanks 3 inundation depth, velocity and tsunami wave load at each of the 8 red points with surrounding tanks we didn t measure inundation depth, velocity and tsunami wave load at the same time 2016/1/13 11
3.Experimental results
The movie of this experiment 2016/1/13 13
The movie of this experiment 2016/1/13 14
Inundation depth (cm) Horizontal component of Tsunami wave load (N) the horizontal component of the tsunami wave load the difference among the three cases Case-1 at point a-2 Case-1 back row middle row front row When reflected waves from surrounding terrain and oil walls acted on the tank the tsunami wave load reached the maximum velocity (cm/s) 2016/1/13 15
velocity (cm/s) velocity (cm/s) Inundation depth (cm) Inundation depth (cm) Horizontal component of Tsunami wave load (N) Horizontal component of Tsunami wave load (N) the horizontal component of the tsunami wave load the difference among the three cases Case-2/3 at point a-2 Case-2 Case-3 In both cases, when tsunami acted a tank, the tsunami wave load reached the maximum 2016/1/13 16
velocity (cm/s) velocity (cm/s) Inundation depth (cm) Inundation depth (cm) Horizontal component of Tsunami wave load (N) Horizontal component of Tsunami wave load (N) the horizontal component of the tsunami wave load the difference among the three cases Case-2/3 at point a-2 Case-2 Case-3 In case3, after a tank started to be inundated, the tsunami wave load reached relatively large peaks and they correspond to the increase in the inundation depth 2016/1/13 17
(N) the vertical component of the tsunami wave load Comparison between the measured tsunami wave load and the buoyancy calculated by assuming the hydrostatics condition back row middle row front row Case-1 at point b-3 Case-3 at point d-1 2016/1/13 18
(N) the vertical component of the tsunami wave load Comparison between the measured at point tsunami b-3 wave load The calculated and buoyancy the buoyancy is in good calculated agreement by with assuming the measured the hydrostatics tsunami wave condition load back row middle row front row Case-1 at point b-3 Case-3 at point d-1 2016/1/13 19
(N) the vertical component of the tsunami wave load Comparison between the measured at at point tsunami d-1 b-3 wave load The calculated and buoyancy the buoyancy is in good overestimated calculated agreement by with the assuming the measured the hydrostatics tsunami wave condition load back row middle row front row Case-1 at point b-3 Case-3 at point d-1 2016/1/13 20
Horizontal component of Tsunami wave load (N) Comparison without and with the surrounding tanks the horizontal component at point b-3 the tsunami wave load acting on a tank with the surrounding tanks by the incident wave is less than that without the surrounding tanks back row middle row front row the sheltering effect of tanks in the front and the middle row Case-2 at point b-3 Case-2 at point c-2 With the surrounding tanks Without the surrounding tanks 2016/1/13 21
Horizontal component of Tsunami wave load (N) Comparison without and with the surrounding tanks the horizontal component In the back row the change with the surrounding tanks is different from the change without the surrounding tanks back row middle row front row Case-2 at point b-3 Case-2 at point c-2 With the surrounding tanks Without the surrounding tanks 2016/1/13 22
Horizontal component of Tsunami wave load (N) Comparison without and with the surrounding tanks the horizontal component In at the point back c-2 row the change with the surrounding tanks Possibility of increasing the tsunami wave load is different from because the change of the presence without the of the surrounding surrounding tanks tanks back row middle row front row Case-2 at point b-3 Case-2 at point c-2 With the surrounding tanks Without the surrounding tanks 2016/1/13 23
Horizontal component of Tsunami wave load (N) Comparison without and with the surrounding tanks the horizontal component in In the the middle back row the change with the surrounding tanks is is different similar from to the the change without the surrounding tanks tanks back row middle row front row Case-2 at point b-3 Case-2 at point c-2 With the surrounding tanks Without the surrounding tanks 2016/1/13 24
Maximum tsunami wave load with the surrounding tanks(n) Maximum tsunami wave load with the surrounding tanks(n) Comparison without and with the surrounding tanks the maximum the tsunami wave load on a tank the horizontal component the vertical component Maximum tsunami wave load without the surrounding tanks(n) Maximum tsunami wave load without the surrounding tanks(n) Regarding the vertical maximum component horizontal component we the didn t tsunami see wave any clear load on difference a tank without between the the surrounding maximum vertical tanks tsunami wave load on was a mostly tank with larger and than without that the with surrounding the surrounding tanks tanks among three cases 2016/1/13 25
Maximum tsunami wave load with the surrounding tanks(n) Maximum tsunami wave load with the surrounding tanks(n) Comparison without and with the surrounding tanks the maximum the tsunami wave load on a tank the horizontal component the vertical component Maximum tsunami wave load without the surrounding tanks(n) Maximum tsunami wave load without the surrounding tanks(n) Regarding the vertical component we didn t see any clear difference between the maximum vertical tsunami wave load on a tank with and without the surrounding tanks among three cases 2016/1/13 26
Characteristic of impulsive force the applicability of conventional formulae Asakura fomula F I ρgdη 2 Equation based on slamming into water F I ρdc 2 η ρdu 2 η we can see the difference between the proportion relativity in the front low and in the middle and the back low ρ: water density g: gravitaional acceleration D: diameter u:velocity η: inundation depth d-3 b-3 b-3 d-3 Asakura fomula Equation based on slamming into water 2016/1/13 27
Characteristic of impulsive force the applicability of conventional formulae Asakura fomula F I ρgdη 2 Equation based on slamming into water F I ρdc 2 η ρdu 2 η We have not obtained a clear relation so far So, we need the further discussion ρ: water density g: gravitaional acceleration D: diameter u:velocity η: inundation depth d-3 b-3 b-3 d-3 Asakura fomula Equation based on slamming into water 2016/1/13 28
4.Conclusion
Conclusion The vertical component of the tsunami load on a tank was well estimated by the buoyancy calculated form the water surface elevation when the wave surface elevation was small. From the comparison between the tsunami wave load with and without the surrounding tanks, the maximum horizontal component of tsunami wave load with the surrounding tanks was smaller than that without the surrounding tanks. In addition, the possibility of increasing of the tsunami wave load was found because of the presence of the surrounding tanks. For impulsive force we can use Asakura formula, but we should change the wave force coefficient according to the distance from the seawall. 2016/1/13 30