Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Newtons law of viscosity

14,804 views

Published on

newtonian and non-newtonian fluids

Published in: Engineering
  • My personal experience with research paper writing services was highly positive. I sent a request to ⇒ www.HelpWriting.net ⇐ and found a writer within a few minutes. Because I had to move house and I literally didn’t have any time to sit on a computer for many hours every evening. Thankfully, the writer I chose followed my instructions to the letter. I know we can all write essays ourselves. For those in the same situation I was in, I recommend ⇒ www.HelpWriting.net ⇐.
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • Sex in your area is here: ❤❤❤ http://bit.ly/39sFWPG ❤❤❤
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • Dating direct: ♥♥♥ http://bit.ly/39sFWPG ♥♥♥
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

Newtons law of viscosity

  1. 1. NEWTON’S LAW OF VISCOSITY Newton’s law of viscosity states that “shear stress is directly proportional to velocity gradient”. The shear stress between the two adjacent layers of fluid is directly proportional to the negative value of the velocity gradient between the same two adjacent fluid layers. Mathematically the law can be stated as:- τyx = - µ dVx / dy Where µ is the constant of proportionality known as dynamic viscosity having units n.s / m2. NEWTONIAN FLUIDS The fluids that obey the newton’s law of viscosity are known as Newtonian fluids. NON NEWTONIAN FLUIDS The fluids that do not obey newton’s law of viscosity are called as Non-Newtonian fluids. TYPES OF NON NEWTONIAN FLUIDS Non-Newtonian fluids are divided into two broad categories on the basis of their shear stress/shear rate behavior as:- Those whose shear stress is dependent on time. Those whose shear stress is independent of time. FIGURE 1 SHEAR DIAGRAM FOR NEWTONIAN AND TIME-INDEPENDENTNON-NEWTONIAN FLUIDS NON-NEWTONIAN FLUIDS (SHEAR STRESS IS INDEPENDENT OF TIME) BINGHAM PLASTIC FLUIDS These are the simplest types of Non-Newtonian fluids. They differ from Newtonian fluids only in the linear relationship that they do not pass through origin. Examples:
  2. 2. Soap Toothpaste Paper Pulp Sewage Sludge Chocolate Mixtures PSEUDO PLASTIC FLUIDS The majority of non-Newtonian fluids are included in this category. Flow behavior of pseudo plastic fluids show and decrease in apparent viscosity with increase in shear rate. Examples: Polymer Solutions Greases Starch Suspensions Biological Fluids Detergent Slurries DILATANT FLUIDS These fluids are less common than pseudo plastic fluids. Flow behavior of dilatant fluids show an increase in apparent viscosity with increase in shear rate. Examples: Corn Flour Sugar Solutions Wet Beach Sand Starch In Water Potassium Silicate In Water FIGURE 2 VISCOSITY SHEAR OVERTIME DIAGRAM FOR TIME-DEPENDENT NON-NEWTONIAN FLUIDS NON-NEWTONIAN FLUIDS (SHEAR STRESS IS DEPENDENT OF TIME) THIXOTROPIC FLUIDS
  3. 3. These fluids exhibit a reversible decrease in shear stress with time at a constant shear rate. Examples: Polymer Solutions, Food Materials Paints RHEOPECTIC FLUIDS These fluids are quite rare in occurrence. These fluids exhibit a reversible increase in shear stress with time at a constant shear rate. Examples: Bentonite Clay Suspensions Solutions and Clay Suspensions VISCOELASTIC FLUIDS In addition to these Non-Newtonian fluids some Non-Newtonian fluids exhibit elastic behavior and are called as viscoelastic fluids. Examples: Flour Dough Polymer Melts

×