Temporal Moment‐Generating Equations: Modeling Transport and Mass Transfer in Heterogeneous Aquifers

摘要: We present an efficient method for determining temporal moments of concentration a solute subject to first-order and diffusive mass transfer in steady velocity fields. The differential equations the all orders have same form as state nonreactive transport equation. Thus can be calculated by code that was written simulate transport, even though actual system is reactive transient. Higher-order are found recursively from lower-order moments. For many cases small number sufficiently describe movement plume. first four accumulated mass, mean, spread, skewness histories at locations. Actual any location approximated applying principle maximum entropy, constraint consistent with physical process dispersion. forms moment-generating different models provide insight into through heterogeneous aquifers. we considered, zeroth moment aquifer independent coefficients. Thus, if field known, transported past point, or out boundary, without knowledge spatial pattern coefficients and, fact, whether occurring. Also, both models, mean arrival time depends on distribution coefficient but values rate coefficients, regardless variability groundwater