Abstract
Desmarais' method for computing the incomplete Struve function in the unsteady lifting surface kernel function is world-famous. It was adopted in a lifting surface computation method, PCKFM, which is also highly evaluated in USA. As a representative of Desmarais' method, “D 12. 1” is investigated in this report, being compared with the method developed by us previously. It is found that Desmarais' method has an own defect that it becomes erroneous in proximity to the X-axis. Moreover it treats numerically some parts of the singularities of the kernel function, which is a violation of general numerical rules. Thus although there is a little merit resulting from computer time, we could not appreciate the Desmarais' method because of the above-mentioned defects.
