Backward facing step flow isothermal cfd benchmarks. Steady turbulent flow over a backwardfacing step is simulated using openfoam. The predictions were carried out with the help of a finitevolume navierstokes solver equipped with a covisualization facility which allows one to investigate the flow dynamics at high temporal resolution. In this demonstration, an enclosure will need to be created around the step and air will be used as the flow material.
Fluid flow over a backward or forward facing step generates recirculation zones and subsequent reattachment regions, due to sudden contraction or expansion in flow passages. Assignment for the course cfd with opensource software of21x. Numerical grid for the flow past a backward facing step rans3d fluent figure 4. The particular data given here are from driver and seegmiller. On simulation of backward facing step flow using immersed. The purpose of this project is to develop two and threedimensional cfd models of the backward facing step flow using ansys fluent, and validate the results by referring to prior research.
This code was created as a final project for a cfd course. This paper details the numerical investigation of 2d laminar flow over a backward facing step in hydrodynamically developing regions entrance region as well in the hydrodynamically developed regions using ibm. In this example we shall investigate supersonic flow over a forward facing step. Backwardfacing step flows for various expansion ratios at low and moderate reynolds numbers this paper is concerned with the behavior of. Flow is isothermal and in the different regimes, from laminar to transition further. This example introduces the following openfoam features for the first time. Moreover each free tutorial or article shared by cfd training is intended to support and help the openfoam users community. Pdf computational investigation of backwardfacing step flow. A developed steady turbulent flow enters through the inlet, passes over the step where it detaches from the boundary and further reattaches at a particular length. Cfd simulation of heat transfer and turbulent fluid flow. Numerical investigation of fluid flow through a 2d.
Kim and moin11 computed ow over a backward facing step using fractional step method, which is second order accurate in both space and time. Literature is extensive, with contributions from experimental, theoretical and computational fluid dynamics. Numerical investigation of backward facing step flow over. Researchers have used the method for many years as a research tool, see e. Hic 2016 numerical investigation of backward facing step flow over various step angles hoi hyun choia, van thinh nguyenb0f0f0f, john nguyenc a,bdept. Tutorial cfd simulation of backward facing step learncax. The backwardfacing step flow has a separation resembling those found in. The code can be run from the command terminal using the following format. The backward facing step is considered by most as the ideal canonical separated ow geometry because of its single xed separation point and the wake dynamics unperturbed by the downstream disturbances. Setting up 2d backward facing step using converge cfd. Turbulent flow over a backwardfacing step cfd autodesk.
Here we are using different mesh sizes to observe the variations of different attributes such as mass flow rate,pressure,velocity and total cells generated. Commercial software ansys fluent has been used to resolve the flow field especially the. Characteristics of flow over a double backwardfacing step. The backwards facing step problem has been one of the first problems to be investigated both in conventional and computational fluid dynamics. Flow over a backwards facing step is a classic computational fluid dynamics test flow in driven cavity stationary and laminar incompressible flow in a square cavity reynolds number. Many practical engineering applications, such as the cooling of electronic devices, open channels, powergenerating equipment, heat exchangers, combustion chambers, and. Although the geometry is very simple, the flow can feature interesting separation regions, which also makes it an ideal candidate for testing numerical boundary conditions as well. Step 4 ansys fluent turbulent flow over a backward facing step. On simulation of backward facing step flow using immersed boundary method c.
Treatment of complex geometries with fluidsolid interaction has been one of the challenging issues in cfd. The unstructured grid method and the immersed boundary method ibm are two different approaches that have been developed so far. Cfd code for flow over backward facing step 4 commits 1 branch 0. Flow over backward facing step mesh turbulent kinetic energy streamlines colored by velocity mag. In this tutorial, we will set up a 2d grid and solve the flow using answer v5. Popular cfd software include answer, porflow, tidal and radm, as well as cfd studio, the new integrated development environment for cfd aplications. Turbulent backward facing step studies the bfs flow has been studied intensively for at least four decades and is possibly the most popular benchmark flow. Im very new to openfoam and trying to do my first assignment on a backwards facing step. The aim of this test case is to validate steadystate flow over a backwardfacing step. The work is focused on numeric investigation of fluid flow through a 2d backward facing step channel with an expansion ratio of 1. Backward facing step using simple algorithm cfd online. The researchers concluded that validation parameters chosen for the study are the locations of the surface hydrostatic pressure and the reattachment compres.
An illustration of the wake characteristics behind a backwardfacing step is shown in figure 1. Pdf cfd analysis of a backward facing step flows researchgate. Adverse pressure gradient, forward facing step, turbulent flow, particle image velocimetry, proper orthogonal decomposition, twopoint correlation, computational fluid. The internal flow over a backward facing step in the transitional regime re d 6000 was studied based on direct numerical simulations. Furthermore, increasing the blockage at constant reynolds number, the x l values decrease. Autoplay when autoplay is enabled, a suggested video will automatically play next. Simulating 2d backward facing step using converge cfd for. This is studied with a view to application to gas turbine combustors. Numerical investigation of fluid flow through a 2d backward. Advanced tutorials proposed by cfd training are designed to model realworld cases in an efficient way for industrial applications of the code. Step 5 using discrete phase model dpm for cfd erosion simulation in a elbow pipe ansys wb fluent tutorial. In this case, the flow is subjected to a sudden increase of crosssectional area, resulting in a separation of flow starting at the point of expansion.
Flow is isothermal and in the different regimes, from laminar to transition further to fully developed turbulent regime. The backwardfacing step is another common test case for cfd codes. Backwardfacing step bfs is arguably the most used and benchmarked geometry for numerical cfd and experimental flow analysis which involves laminar flow, recirculating turbulent flow and. The cfd domain consists of inlet, backward facing step and an outlet. The cfd results show that as the step angle is increased, x l decreased. Flow through a backward facing step is one of the classical. The problem description involves a flow of mach 3 at an inlet to a rectangular geometry with a step near the inlet region that generates shock waves.
The only tutorial or info i have had so far is meshing a backwards facing step cfd online discussion forums. The heated turbulent flow over a backward facing step is numerically solved using the commercial computational fluid dynamics program fluent. On the flow characteristics behind a backwardfacing step. The main point of this paper is incompressible flow in a backward step, measured by drivers and seegmiller experiments. Introduction the indoor environment community has adopted computational fluid dynamics cfd as a useful tool for the prediction of air movement in ventilated spaces. Simulation of steady, laminar flow over a backwardfacing. Chpr4407 assignment 2 flow over a backwardsfacing step.
The flow over backward facing step is one of the important prototypes used to study the separation flows. Jayaraj department of mechanical engineering, national institute of technology, calicut, 673 601 india. Simple 2d backward facing step simulation using converge. The simulation is carried for three different base mesh 2e3, 1. Flow over a backward facing step with parabolic velocity profile at inlet. This tutorial is based on cfd modeling software ansys fluent and will cover simulation steps and post processing required to solve steady state, turbulent flow. Turbulent flow over a backwardfacing step cfd 2016. In this case, a turbulent boundary layer encounters a sudden back step, causing flow separation. Both fundamental experimental and numerical studies have been carried out by many investigators. It simulates a steady 2d flow over a backward facing step. Numerical investigation of backward facing step flow over various step angles. Flow over a backwardfacing step cfd simulation library. Student were taught how to get the data for geometry, materials properties and flow conditions from research paper.
How to add a passive scalar to your openfoam simulations. To predict transitional and fully developed turbulent flow. It can be considered as a simply supply flow scenario in building ventilation. Backward flow simulation using converge studio this present project comprises the simulation of the backwardfacing step using converge cfd software. Step 6 ansys wb cfd tutorial of laminar flow in 3d circular pipe. Numerical simulation of a turbulent flow over a backward. Assignment for the course cfd with opensource software. How to achieve a cfd flow over a backward facing step with parabolic velocity profile at inflow simulation. Experimental case described by driver and seegmiller 11. Computational fluid dynamics cfd simulations using reynoldsaveraged navierstokes rans turbulence models. Turbulent flow over a backwardfacing step cfd 2019. The dynamics of the transitional flow over a backward. I am now working to solve the backward facing step flow backward facing step using simple algorithm cfd online discussion forums. Experimental and numerical studies of flows over forward.
Boundary conditions appropriate for the cfd are shown in the following figure. For this particular essentially incompressible backward facing step problem. The incompressible, turbulent case is validated with the experimental results of driver and seegmiller 1 as archived in the nasa turbulence modeling resource 2. Commercial software ansys fluent has been used to resolve the flow field especially the separation length. A typical gas turbine combustion chamber flow presents similarities with the wellstudied case of turbulent flow over a backward facing step, especially in the nearwall regions where the heat transfer phenomena take place. Boundary conditions for the flow past a backward facing step 4. An experiment was conducted on fine structures of supersonic laminarturbulent flow over a backward facing step as discussed by chen et al. They reported multiple recirculation zones downstream of the step. This case examines flow over a backwardfacing step. Backwardfacing step flows for various expansion ratios at. Step 7 ansys wb fluent cfd tutorial of a slug flow using multiphase vof model.
The incompressible, turbulent case is validated with the experimental results of driver and seegmiller 1 as archived. Learn how to do a 2d backward facing step in ansys fluent. The geometry of the flow scenario, along with the general nomenclature, is shown in figure 1. Analysis characteristics steadystate 2d internal, separated flow turbulent incompressible reference vogel, j. The backward facing step is an interesting case for studying the performance and solution strategy of a turbulence model. The benchmark describes a backwardfacing step flow problem, also known as sudden expansion flow. By browsing our site, closing this message, or clicking accept all cookies, you agree to store cookies by us and thirdparty partners.
856 1623 898 1665 331 243 547 586 731 649 143 876 412 331 1058 1000 836 1619 1196 1399 1111 1588 503 173 595 482 224 1244 847 1026 1347 156 318 1298 381 538 319 964 10 457 221 657 461