Numerical modelling of airflow over an idealised transverse dune
نویسندگان
چکیده
The general flow structure over transverse aeolian dunes is now well documented through both field studies and wind tunnel experiments. Research on windward (stoss) slopes of dunes is extensive and has recently been complemented by research on the lee-side flow structure. However, a number of technical deficiencies in wind tunnel instrumentation and a lack of detailed resolution in and appropriate turbulence instrumentation for field research have resulted in an incomplete quantified characterisation of the flow structure over aeolian dunes. This study applies a two-dimensional numerical model with an RNG-modified turbulence model to simulate the time-averaged flow field over an idealized aeolian dune. The model is successfully validated with wind tunnel experimental data. Results indicate that the model accurately predicts the flow patterns over the dune, producing regions of flow stagnation at the toe, acceleration up the stoss slope and a region of flow separation and reversal in the lee. Further development and application of this model will allow examination of flow-form interaction, the testing of more complex isolated dune morphologies, and characterisation of flow over multiple dunes. 2003 Elsevier Ltd. All rights reserved.
منابع مشابه
Two-dimensional airflow modeling underpredicts the wind velocity over dunes
We investigate the average turbulent wind field over a barchan dune by means of Computational Fluid Dynamics. We find that the fractional speed-up ratio of the wind velocity over the three-dimensional barchan shape differs from the one obtained from two-dimensional calculations of the airflow over the longitudinal cut along the dune's symmetry axis - that is, over the equivalent transverse dune...
متن کاملNumerical modelling of flow structures over transverse aeolian dunes
Numerical flow models have been widely applied in engineering disciplines for many years. In the last few years, there has been a proliferation of the use of Computational Fluid Dynamics (CFD) in the fields of geomorphology and hydrology (see Bates and Lane, 1998). These models enable an improved simulation of important processes providing prediction fields that allow considerable insight into ...
متن کاملSand transverse dune aerodynamics: 3D Coherent Flow Structures from a computational study
The engineering interest about dune fields is dictated by the their interaction with a number of human infrastructures in arid environments. Sand dunes dynamics is dictated by wind and its ability to induce sand erosion, transport and deposition. A deep understanding of dune aerodynamics serves then to ground effective strategies for the protection of human infrastructures from sand, the so-cal...
متن کاملMeasuring a transverse dune field in the Lençóis Maranhenses
In this work, we present measurements of the height profile, wind velocity and sand flux performed on transverse dunes in the dune field known as “Lençóis Maranhenses”, northeastern Brazil. From the measured profile, we selected one dune to measure the air shear stress and the sand flux and compared the results with the theoretical predictions from a dune model in two dimensions recently introd...
متن کاملNumerical modeling of the wind flow over a transverse dune
Transverse dunes, which form under unidirectional winds and have fixed profile in the direction perpendicular to the wind, occur on all celestial objects of our solar system where dunes have been detected. Here we perform a numerical study of the average turbulent wind flow over a transverse dune by means of computational fluid dynamics simulations. We find that the length of the zone of recirc...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Environmental Modelling and Software
دوره 19 شماره
صفحات -
تاریخ انتشار 2004