In this work, we use the homogenization theory to investigate the capability of wavy riblet patterns to influence the behaviour of a viscous flow near a ribbed boundary. Starting from perfect slip conditions on the wall, we show that periodic oscillations of wavy riblets in the lateral direction may induce a friction effect in the direction of the flow, contrary to what happens with straight ri...

We study the flow of an incompressible liquid film down a wavy incline. Applying a Galerkin method with only one ansatz function to the Navier–Stokes equations we derive a second order weighted residual integral boundary layer equation, which in particular may be used to describe eddies in the troughs of the wavy bottom. We present numerical results which show that our model is qualitatively an...

The stability of wavy supercritical cylindrical Couette flow has been studied extensively, but few measurements of the velocity field in flow have been made. Particle image velocimetry was used to measure the azimuthal and radial velocities in latitudinal planes perpendicular to the axis of rotation for wavy cylindrical Couette flow in the annulus between a rotating inner cylinder and a fixed o...

This experimental and phenomenological study investigated fluctuations characteristic frequencies of pressure drop flow pattern during boiling isobutane in a horizontal mini-channel 1.0 mm diameter. The fluid was at saturation condition 27°C, heat flux ranging between 1 80 kW/m² mass from 380 to 890 kg/(m²s). Six different patterns were identified based on the analysis images captured high-spee...

A flow transition in a coaxial rotating cylinder with only inner cylinder rotation was investigated using ultrasonic Doppler method for a wide range of Reynolds number up to 40 times critical Reynolds number (Rc). By analysing spatio-temporal velocity profiles, excitation functions of various transition modes such as wavy and modulated wavy modes were obtained using space-time Fourier expansion...

The present study investigates the effect of outer diameter (10 mm and 15 mm) 5 positions cylindrical vortex generators (CVGs) installed to wavy channel in order improve heat transfer parameters conjunction with low-pressure drops. channels without CVGs are compared terms local coefficient, mean Nusselt number, Colburn factor, friction, thermal performance for Re range 857 8001. Furthermore, co...

The current work aims to inspect the influence of formation flow on hydrothermal performance and uniformity base temperature in serpentine mini channel heat sink. study was conducted by changing with straight model [A] wavy [B] place inlet outlet putting entrance at sink center using water as working fluid. To obtain numerical results, a 3D (ANSYS Fluent program) is used. A comparison between f...