Measurements of the Effective Tensile Strength of Newtonian and Non-Newtonian Fluids Under Dynamic Stressing

The ‘Bullet-Piston’ (B-P) dynamic stressing technique has been used to study the tensile strength, F_c, of Newtonian and non-Newtonian fluids. A comparative study of the effects of viscosity on F_c for silicone oils (Newtonian) and aqueous polyacrylamide (PAA) solutions (non-Newtonian) was made. Both systems exhibited a power law dependency of the form F_c ∝ µⁿ, where µ is the viscosity and n is the power index. For the Newtonian system, n was found to be 0.09 in close agreement with the findings of Couzens and Trevena (1974) for silicone oils whilst a value of 0.16 was found for the PAA solutions.