非均质性对非饱和-饱和系统水流时空变化的作用

摘要

Under white noise infiltration, the temporospatial variations of pressure head in an unsaturated-saturated system were studied. Both the homogeneous and heterogeneous systems were considered. Damping effect of the system and effect of the heterogeneity on the fluctuations of the water flow were analyzed. Results show that both the homogeneous and heterogeneous systems damp the fluctuations of the pressure head as the variance, auto-covariance and power spectrum decrease with depth. The fluctuations of pressure head are non-stationary at early time due to the initial conditions and become stationary at late time. Heterogeneity strengthens the fluctuations of the pressure head and weakens the short-term correlation. The fluctuations of pressure head are mainly caused by the heterogeneity of the system.%通过模拟均质和非均质两种情形下非饱和—饱和系统中压力水头的时空变化，研究非饱和—饱和系统对水流波动的阻尼作用和系统非均质性对水流波动的作用。结果显示，两种情形下非饱和—饱和系统对水流波动均有阻尼作用，随深度增加，压力水头波动减弱，方差、自协方差和功率谱减小；压力水头在早期因初始条件做非平稳波动，而后随时间增长演变为平稳波动；系统的非均质性加剧了压力水头的波动，是波动的主要来源，使得压力水头方差、自协方差和功率谱增大；非均质性减小压力水头波动的短期相关性。