Boundary Layer Concepts

This lecture covers the concepts related to boundary layers, including the impact of viscosity, the transition from laminar to turbulent flow, and the analysis of drag and lift forces. It also discusses the dimensional analysis of pipe flow and the importance of the Navier-Stokes equations in solving special cases. The presentation delves into the Moody chart for fluid flow, the Prandtl boundary layer theory, and the application of potential flow theory in understanding drag forces. Additionally, it explores the effects of pressure distribution and shear stress on surfaces, emphasizing the significance of boundary layer thickness in fluid dynamics.

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related lectures (183)

Related concepts (52)

ME-344: Incompressible fluid mechanics

Basic lecture in incompressible fluid mechanics

Viscosity

The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity is defined scientifically as a force multiplied by a time divided by an area. Thus its SI units are newton-seconds per square metre, or pascal-seconds. Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion.

Dimension

In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coordinate is needed to specify a point on it - for example, the point at 5 on a number line. A surface, such as the boundary of a cylinder or sphere, has a dimension of two (2D) because two coordinates are needed to specify a point on it - for example, both a latitude and longitude are required to locate a point on the surface of a sphere.

Four-dimensional space

Four-dimensional space (4D) is the mathematical extension of the concept of three-dimensional space (3D). Three-dimensional space is the simplest possible abstraction of the observation that one needs only three numbers, called dimensions, to describe the sizes or locations of objects in the everyday world. For example, the volume of a rectangular box is found by measuring and multiplying its length, width, and height (often labeled x, y, and z).

Boundary layer

In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary condition (zero velocity at the wall). The flow velocity then monotonically increases above the surface until it returns to the bulk flow velocity. The thin layer consisting of fluid whose velocity has not yet returned to the bulk flow velocity is called the velocity boundary layer.

Newtonian fluid

A Newtonian fluid is a fluid in which the viscous stresses arising from its flow are at every point linearly correlated to the local strain rate — the rate of change of its deformation over time. Stresses are proportional to the rate of change of the fluid's velocity vector. A fluid is Newtonian only if the tensors that describe the viscous stress and the strain rate are related by a constant viscosity tensor that does not depend on the stress state and velocity of the flow.

Turbulence: Numerical Flow Simulation ME-474: Numerical flow simulation

Explores turbulence characteristics, simulation methods, and modeling challenges, providing guidelines for choosing and validating turbulence models.

Boundary Layers: Recap and Effects on Drag and Lift ME-344: Incompressible fluid mechanics

Covers the importance of boundary layers, viscosity effects on drag and lift.

Drag on a Sphere and Newtonian Fluid Mechanics ME-201: Continuum mechanics

Covers the analysis of drag on a sphere in Newtonian fluid mechanics, focusing on key parameters and the significance of Reynolds number.

Viscous Flow: Laminar Shear Men ME-280: Fluid mechanics (for GM)

Explores the concept of laminar shear men in viscous flow in pipes.

Laminar Shear Flow: Parallel Plates ME-280: Fluid mechanics (for GM)

Analyzes laminar shear flow between parallel plates, discussing nonlinear equations and flow assumptions.