本研究利用高速攝影技術並架設兩種實驗對二維顆粒的碰撞進行研究。
實驗一是利用不鏽鋼珠,控制於某一固定高度,並使其沿著阻礙物自由落下至玻璃平板上進行碰撞,進而觀察顆粒的能量耗散。當顆粒在玻璃平台上互相碰撞時,其能量的變化為E = E_0*e^{-r_d*tau}, (E為平均顆粒的能量、E_0為平均顆粒的能量初始能量、r_d為耗散率、tau為平均顆粒累加碰撞數)。而從實驗中可以得到r_d約為0.73,另外由電腦模擬得到的r_d約為0.23,因此可知道實驗中顆粒的能量消散比模擬的結果還要快,其原因可能是在實驗裡,顆粒與玻璃平台之間有互相作用所造成的。

實驗二則使用射彈去撞擊由不鏽鋼珠所組成的顆粒矩陣,而顆粒矩陣為間距為L的二維方形晶格。
實驗中,射彈會用不同的入射速度(u_{0x})碰擊顆粒矩陣,可以發現射彈在顆粒矩陣中的速度為u_x = u_(0x)*e^(-Gamma*t)(Gamma為衰減率)。
當射彈以對稱非中心去碰撞顆粒矩陣的第一排時,可以發現衰減率(Gamma)會隨入射速度(u_(0x))增加而變小,且可找到Gamma = a-bu_(0x);而從碰撞原理推導的經驗方程式中,也可以算出a和b,最後可發現,理論結果和實驗很接近。

We study the energy dissipation of two-dimensional granular gas using a high speed photography. In the first experiment, stainless steel spheres are used to fall along the inside wall of a hemispheric shell into a horizontal plate where they collid with each other and the average kinetic energy per particle was measured.
We find that the average kinetic energy per particle (E) of the granular gas decaies exponentially in E = E_0*e^{-r_d*tau} and decay rate(r_d) is predicted 0.7.
However, in computer simulation, decay rete(r_d) is about 0.23. We find that energy dissipates more rapidly in the experimental systems than that of the simulation, due in large part to the interactions of the particles with surface and glass baffle.
In the second experiment, we use a projectile at various inlet velocities (u_(0x)) and positions(b) to collided granular matrix which comprises stainless steel spheres.
We find that velocity of projectile (u_x) decaies exponentially in u_x = u_(0x)*e^{Gamma*t} where Gamma is decay time.
In the case of b = 2.75 mm, decay time decreases with the increasing of inlet velocity and a fitted formula is found, Gamma = a-b*u_(0x). Finally, we find that theoretical and experimental results for decay time are very close.

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