Long-term Research Objective: The scientific objectives of this project are: 1. To describe and characterize the physical mechanisms which determine how most of the noise radiates from a finite fluid-filled pipe with turbulent flow. 2. To determine criteria which estimate the relative importance of these various mechanisms. 3. To develop experimental and analytical techniques for investigating ...

Mathematical modeling plays an important role whenever flow investigations are performed. In this paper special emphasis was given to models which are used in turbulent flow simulations and the effect of numerical discretization. The numerical scheme is of great importance when direct numerical simulations, i.e. the solution of the Navier-Stokes equations without any additional turbulence model...

The dynamical theory of moderate Reynolds number turbulence triangulates the infinite-dimensional Navier-Stokes state space by sets of exact solutions (equilibria, relative equilibria, periodic orbits, ...) which form a rigid backbone which enables us to describe and predict the sinuous motions of a turbulent fluid. We report determination of a set of unstable periodic orbits from close recurre...

The turbulent potential model is a RANS model that avoids modeling the Reynolds stress tensor. As a result it has the ability to obtain the physical accuracy of Reynolds stress transport equation models at a cost and complexity comparable to popular two equation models. The model’s ability to predict channel flow, free-shear layers, homogeneous shear flow, stagnation point flow, backward facing...

in the present work, graphene was synthesized by chemical vapor deposition (cvd) method. the structure of graphene was then confirmed by x-ray diffraction (xrd) and scanning electron microscope (tem) images. after that, mixed acid method (h2so4/hno3) was used to make the structure of synthesized graphenehydrophilic. in this method, carboxylate and hydroxide groups were linked to the edges of gr...

We describe a method to investigate the mode shapes in turbulent pipe flow at a given wavenumber pair that are most responsive to harmonic forcing in the sense that the they correspond to the largest singular value in a Schmidt decomposition of the linear NavierStokes operator using the turbulent mean profile as the base flow. The ideas follow logically from the work of Sharma & McKeon (2009), ...

Future rocket-nozzle extensions have to be thermally protected by a film of cooling gas. The hot supersonic boundary-layer flow may be fully turbulent despite a strong favorable pressure gradient and strongly cooled walls. In contrast to previous investigations, where a laminar boundary-layer state was considered, the present work deals with the effects of a turbulent flow. The cooling film is ...

Shock-boundary layer interaction (SBLI) is a kind of problem which is frequently met in supersonic engine inlet flow and external flow. A detail study on mechanism of reduction of shock induced flow separation by MVG is carried out by high order implicit large eddy simulation (LES). To generate the fully developed turbulent flow, a series of turbulent profiles are given by previous DNS simulati...

Film cooling systems induce a range of complex phenomena associated with the interaction of the coolant jet discharging into a crossflow. The jet-in-crossflow configuration has been extensively studied through experiments and direct/large-eddy numerical simulations. However, most previous simulations consider a laminar crossflow and a transverse jet originating from a fully developed pipe flow ...