I believe mechanical polishing would be an adequate solution.

Is important to know what type of roughness parameter you speak. For example, if Ra=1micrometer, is possible to obtain by finish turning (little nose radius tool and little feed too).

Microblasting with a right mixture of abrasive particles along with appropriate operational parameters will make it.

There are a relation between the machining method and the roughness value. Can explain what roughness parameter do you need please?

Hi Daniel M Krahmer thanks for your interest. I don't have sound knowledge on type of roughness. I want to exploit the finding by Wenzel that cosine of liquid contact angle on a rough surface increases by the factor area increases by roughening over area of original polished surface.  http://pubs.acs.org/doi/abs/10.1021/j150474a015

 Hi Yong Gao...I am curious to know about microblasting. I s there any standard equipment which can impact micron size ganules on a surface in controlled manner ?

Please, look the page 10 in the attached file.

I think you need test with differents roughness to find the better behaviour of the surface. 

If you want talk with an turning man, explain your neccesity and he manufacture differents samples for testing.

Magnetic Pulse Forming is a novel approach that is very reliable and repeatable. High pressure impact of substrate to a form die with the desired pattern imparts high energy and embosses the desired surface finish into the work piece.

1. Polishing with silicon carbide paper; 2. Scratching with a nanoindenter; and so on