The corrugations provide an enhancement to the inside film coefficient and there are several papers which cover this, including experimental data.  Consider the following:

J.G. Withers (1980) publications in "Heat Transfer Engineering" Vol 2 No.1 pp 48-58 and No.2 pp 43-50
H. M. Li, et al (1982) publication in "Proceedings 7th International Heat Transfer Conference" Munich, Vol 3 pp 75-80
R. Sethumadhavan & R Rao, (1986) Journal Heat Transfer Vol 108 pp 55-61.