Spreading Dynamics of Shear-Thinning Fluid Drop Impact on Hydrophobic Substrate

نویسندگان

  • Purushothaman Nandagopalan
  • Jerin John
  • Ankur Miglani
  • Seung Wook Baek
چکیده

Droplet impact dynamics of the shear-thinning fluids on the hydrophobic surfaces have been experimentally studied and compared to the base fluid, water. In this work, hydrogels are prepared by lading water with Polyacrylamide polymer at three loading rates 1, 2, and 3 wt. %. The resultant hydrogel phase behaves as a shear thinning fluid with altered rheophysical properties. The presence of polymer additive modifies the entire spread dynamics by reducing the value of maximum spread due to the presence of finite yield stress and also by eliminating the bouncing effect of the base fluid. Despite the effect of inertial spreading of the droplet, dominant viscous forces act as dampers to both during the spreading and receding regimes. In particular, viscous forces prolong the receding period by an order of magnitude while completely suppressing secondary spreading. Finally, it is shown that shear-thinning fluids follow the well-known Tanner’s law (RR αα tt nn 7+3nn ; R: spread radius, t : time and n: shear thinning index), however, with a simple modification involving the substitution of shear thinning index obtained from rheology with the spreading exponent obtained from drop impact experiments.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Yield - stress Drops Guy German

The behaviour of viscoplastic drops during formation and detachment from a capillary nozzle, free-fall, impact on a solid substrate and subsequent spreading are investigated experimentally by high-speed imaging. Drop dynamic behaviour is an integral component of many contemporary industrial processes ranging from fuelinjection systems in combustion engines to spray coating, agrochemical and pha...

متن کامل

Capillarity driven spreading of circular drops of shear-thinning fluid

We investigate the spreading of thin, circular liquid drops of powerlaw rheology. We derive the equation of motion using the thin film approximation, construct source-type similarity solutions and compute the spreading rate, aparent contact angles and height profiles. In contrast with the spreading of newtonian liquids, the contact line paradox does not arise for shear thinning fluids. In this ...

متن کامل

Dynamics of Droplets

Capturing non-Newtonian power-law drops by horizontal thin fibers with circular cross‐ section in a quiescent media can be studied in this chapter. The case is simulated using volume of fluid (VOF) method providing a notable reduction of a computational cost. Open source OpenFOAM software is applied to conduct the simulations. This model is an extension of the one developed earlier by Lorenceau...

متن کامل

Effects of Interfacial and Viscous Properties of Liquids on Drop Spread Dynamics

An experimental study of the post-impact spreading of liquid droplets on dry horizontal substrates is presented in this paper. The drop spreading and recoil behaviors are captured using a high-speed digital video camera at 2000 frames per second. To ascertain the effects of liquid interfacial and viscous properties, experiments were conducted with five liquids (water, ethylene glycol, propylene...

متن کامل

Thin film dynamics on a prolate spheroid with application to the cornea

The tear film on the front of the eye is critical to proper eyesight; in many mathematical models of the tear film, the tear film is assumed to be on a flat substrate. We re-examine this assumption by studying the effect of a substrate which is representative of the human cornea. We study the flow of a thin fluid film on a prolate spheroid which is a good approximation to the shape of the human...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2016