Is there any method to determine viscosity of mixture of non-newtonian fluids? When we mix 50% of shear thinning and 50% shear thickening fluids, which property will be more dominant in the resulting mixture?
You need to mix your solution well and use a viscometer/rheometer to measure the changes in viscosity with an increasing shear rate. You can then determine its shear-thinning/shear-thickening properties from a viscosity-shear rate graph.
When you are mixing the equal proportions of both the additives. The properties of fluid will be of molecular weight, molar mass distribution and chemical class. It is better to mix your solution well as suggested by Ernest Ong and use viscometer/rheolmeter.