The asymptotics of a generalised Struve function

A generalised Struve function has recently been introduced by Ali, Mondal and Nisar [J. Korean Math. Soc. 54 (2017) 575–598] as ( 1 2 z) ν+1 X∞ n=0 ( 1 2 z) 2n Γ(n + 3 2 )Γ(an + ν + 3 2 ) , where a is a positive integer. In this paper, we obtain the asymptotic expansions of this function for large complex z when a is a real parameter satisfying a > −1. Some numerical examples are presented to confirm the accuracy of the expansions.