We develop a reduced-order model for large-scale unsteadiness (vortex shedding) in a two-dimensional diffuser and use the model to show how periodic mass injection near the separation point reduces stagnation pressure loss. The model estimates the characteristic frequency of vortex shedding and stagnation pressure loss by accounting for the accumulated circulation due to the vorticity flux into...

Acoustic stimulation is a promising method for increasing drainage of non-Newtonian fluids through porous structures in various applications. In this study, a mathematical model is developed for unsteady flow of a bi-viscous incompressible fluid in a circular straight channel. Longitudinal vibrations are superimposed on the flow driven by changing pressure gradients along the channel. Simulatio...

The pressure- and temperature-sensitive paint (PSP/TSP) technique, for steady-state and unsteady-state measurements, is becoming widespread. However, unsteady quantitative measurement is still difficult because non-uniform distribution of the probes over a test model may cause errors in the results. We focus on the dipping method that applies two luminophores into a binding material to improve ...

Abstract A segmented annular seal is composed of several identical carbon segments assembled around the rotor by a circumferential (garter) spring. Each segment has one or more pads delimited deep grooves to generate radial lift force when speed rotation not zero. One solutions for enhancing this provide inclined on rotor. This solution analyzed here numerically assuming thin air film between a...

An enhanced displacement feedback structural control procedure is presented for performance-based design in this paper. At first, a comparative study is implemented assessing three most common active control algorithms including state, acceleration, and displacement feedback controls. The advantage of the displacement feedback algorithm for active control of structures against earthquakes is de...

This paper demonstrates efficient solver technologies applied to the non-linear frequency domain (NLFD) method. The basis of the NLFD method is to assume the time period of the solution s oscillation and to transform both the solution and residual using a discrete Fourier transform. An unsteady residual is formed in the frequency domain and iteratively driven to a negligible value. This method ...

Potential flow solvers for 3D aerodynamic flows are commonly used in industrial applications. Two main difficulties preventing the even more widespread use of these codes are the limitations on the number of discretization elements and the user expertise and effort required to specify the wake location. In the paper we present an automatic wake generation strategy for a potential flow solver, a...

active flow control has great importance in design of flying objects in general and control flaps in particular. using dielectric barrier discharge as plasma actuators over control flaps can cause a change in position of separation point or can eliminate it. this new flow control device produces a body force that causes generating a micro wall jet. the present study aims to investigate experime...