I was reading about diffusion-controlled reactions, and on the Wikipedia page (Diffusion-controlled_reaction) it says the following:
"One classical test for diffusion control is to observe whether the rate of reaction is affected by stirring or agitation; if so then the reaction is almost certainly diffusion controlled under those conditions."
How does stirring affect the rate of reaction in this scenario?
I was taught that if a reaction was homogeneous in nature, then stirring should not affect the rate of reaction. I would have thought that if a reaction was homogenous and occurring in a viscous medium, that the rate would not change therefore. So I do not see how stirring a viscous system increases the rate of reaction if it is already homogenous.
UPDATE: Thank you for all the comments so far!
I have done some reading, and I see that stirring can affect the effective diffusion coefficient. This has been demonstrated with the Belousov-Zhabotinsky reaction. According to the paper that I was reading, the effective diffusion coefficient is the sum of the turbulent diffusion coefficient and the molecular diffusion coefficient, and stirring affects the turbulent diffusion coefficient. But what does this actually mean?
Does stirring lead to more collisions and therefore increase in the rate of reaction, or is it to do with changing the shear rate which then influences the observable rate of reaction?