Nonlinear Mechanical Vibrations

Of Related Interest Turbomachine Unsteady Aerodynamics J.S. Rao The problem of blade fatigue failures is important in the design of new gas turbines. The most important information required in estimating the blade life is the non-steady force field arising out of the stage flow path interaction. This book is concerned with such information. Basic principles of inviscid incompressible flows are first presented with applications to elementary incompressible flows. The airfoil theory using conformal mapping is then given to explain the basic principles of steady aerodynamic lift followed by two dimensional thin airfoil theory. The unsteady thin airfoil theory due to transverse and chordwise gusts in the upstream flow is given in detail, which is then linked to the turbomachine stage flow. The blade lift and moment calculations arising out of potential flow and vortex wakes from the neighbouring row are then presented. Next, the principles of compressible flow are introduced with extension to the turbomachine stage problem. A modified exact hydraulic analogy for isentropic flows is then introduced to study flow path interaction in a gas turbine stage. Finally, viscous flow and boundary layer theory are introduced with applications to the turbomachine blades. Thus, this book enables a designer to determine the blade non-steady force field in a turbomachine.