“…Due to its important physical background, exploring its efficient numerical methods is a hot topic in computational mathematics. Since Colton et al [10] proposed three numerical methods, the related scholars sequentially developed many numerical methods, including conforming element methods [22,7,25,16,14], nonconforming element methods [27], spectral methods [1], C 0 IPG methods [12] and boundary element methods [17,28]. Regarding the study of conforming elements, early in 2011 Sun [22] proposed the iterative methods using conforming elements to solve the problem.…”