Hydrodynamics Presented by Mr.Halavath Ramesh M.A,M.sc,B.ED,PGDCAQM,PGDCA,M.Phil,(P.HD)(UoH) University of Madras Dept. of Chemistry Loyola College,Chennai.

INTRODUCTION Hydrodynamic: Hydrodynamic is a branch of physics that deals with the motion of fluids and the forces acting on solid bodies immersed in fluids and in motion relative to them. Diffusion: Diffusion derives from the Latin word, which means” to spread way out”. Diffusion is the net movement of molecules from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in chemical potential of the diffusing species. Gradient: The gradient is a multi-variable generalization of the derivative. Function of several variables. Osmosis: Osmosis is a spontaneous net movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration in the direction that tends to equalize the solute concentration on the two sides. Velocity: The speed at which an object is travelling,velocity is defined as a vector measurement of the rate and direction of motion.

Speed: Radius: Radius is a line from the centre to the outside of the of a circle or sphere. Example. Bike wheel. Diameter: Diameter is a straight line passing from side to side through the centre of a body or figure especially a circle or sphere.

Hydrodynamic Techniques 1. Analytical ultracentrifugation 2. Electrophoresis 3. Electric birefringence 4. Flow birefringence 5. Dynamic Light Scattering 6. Fluorescence correlation spectroscopy 7. Viscosity 8. Diffusion 9. Hydration 10. Friction

Biological macromolecules as hydrodynamic particles Traditionally, hydrodynamic deals with the behaviour of bodies in fluids and in particular, with phenomena in which a force acts on a particle in a viscous in particular, with phenomena in which a force acts on a particles in a viscous solution. Very eminent scientists, such as Isaac Newton, James clerk maxwell,Lord Rayleigh and Albert Einstein,started their careers with major contributions to the science of hydrodynamics. Note that not only are the discoveries from more than 100 years ago still highly relevant today, but also that they continues to stimulate important new developments in the field. Reynolds number we consider an object moving with some velocity through a fluid of specific density and viscosity. The Reynolds number is a dimensionless parameter, which determines the relative importance of inertial and viscous effects Reynolds number = fluid density * speed*particle size ____________________________ =R= ƥ ǔ Ɩ / Viscosity When the Reynolds number is low, viscous forces dominate. If it is high, inertial forces dominate.

Hydration In hydrodynamic experiments, a biological macromolecules moves with a certain amount of bound solvent, thus defining the concept of a hydrated particles as a core of particles material and envelope of bound water. Protein hydration, (gg-1), express the ratio of the mass of the bound water to that of the protein. = grams(water) ____________ gram (protein) Determination of particle friction properties Stick boundary conditions: In stick condition the solvent layer sticks to the particle surface and moves with it. Slip boundary conditions: In slip condition there is no interaction between the solvent and particle and the solvent slips over the particle surface.

Prediction of particle friction properties Modern hydrodynamics allows the prediction of the frictional properties of biological macromolecules of any shape. The computing procedure used essentially depends on the particle shape. 1.Particles of” round “shape 2.Particles with a ‘ broken ‘ shape 3.Particles of arbitrary shape 4.Particles with a known three- dimensional structure