documentclass{standalone}
usepackage{tikz}
usetikzlibrary{datavisualization,datavisualization.formats.functions}
begin{document}
tikz datavisualization
[scientific axes=clean,
visualize as smooth line/.list={sin},
sin={style={red,ultra thick}} %%% <--- style of lines in sin set defined here
]

data [set=sin, format=function] {
var x : interval[0:3*pi];
func y = sin(value x r);
};
end{document}