TWISTER (Twente water injection system for turbulence experimental research): a jet array in the Twente water tunnel for generating strong turbulence using four-dimensional gradient noise

Experiments in Fluids, vol. 66, pp. 184

Abstract

Abstract We present a newly constructed jet array with a novel driving scheme for turbulence generation in a vertical water tunnel and measurements of the turbulent flow this jet array establishes. The design of the array allows us to control the mean background flow and the turbulence intensity independently of each other. The array consists of a rectangular arrangement of 112 individually computer-controlled water jets that are aligned streamwise to the measurement section of our 8-m tall vertically recirculating water tunnel. Using solenoid valves, individual jets are activated following predefined protocols that can be tailored to obtain different turbulence statistics within the measurement section. The protocols are based on four-dimensional OpenSimplex noise, a type of gradient noise that features spatial and temporal coherence. Details of the mechanical and electrical designs are presented, together with a detailed description of the protocol generation. We show that the resulting turbulence is near homogeneous and isotropic, with a turbulence intensity of Order 1, an energy dissipation rate of order $$10^{-1}\,\mathrm {m^2/s^3}$$ 10 - 1 m 2 / s 3 and $$\textrm{Re}_{\lambda }\approx 1400$$ Re λ ≈ 1400 . Additionally, we present experiments that show the effects that various system and protocol parameters have on the created flow conditions and address the streamwise development, as well as the homogeneity and isotropy of the flow.

Authors 4

1. Duco van Buuren corresponding

   University of Twente · Max Planck University of Twente Center for Complex Fluid Dynamics

   Affiliation as printed

   Physics of Fluids Group, J. M. Burgers Center for Fluid Dynamics and Max Planck Center Twente, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands

   Physics of Fluids Group, J. M. Burgers Center for Fluid Dynamics and Max Planck Center Twente, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands

2. Dennis P. M. van Gils

   University of Twente · Max Planck University of Twente Center for Complex Fluid Dynamics

   Affiliation as printed

   Physics of Fluids Group, J. M. Burgers Center for Fluid Dynamics and Max Planck Center Twente, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands

   Physics of Fluids Group, J. M. Burgers Center for Fluid Dynamics and Max Planck Center Twente, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands

3. Gert‐Wim Bruggert

   University of Twente · Max Planck University of Twente Center for Complex Fluid Dynamics

   Affiliation as printed

   Physics of Fluids Group, J. M. Burgers Center for Fluid Dynamics and Max Planck Center Twente, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands

   Physics of Fluids Group, J. M. Burgers Center for Fluid Dynamics and Max Planck Center Twente, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands

4. Dominik J. Krug corresponding Aachen Faculty of Mechanical Engineering Institute of Aerodynamics Chair of Fluid Mechanics

   RWTH Aachen University · University of Twente · Max Planck University of Twente Center for Complex Fluid Dynamics

   Affiliation as printed

   Institute of Aerodynamics and Chair of Fluid Mechanics, Faculty of Mechanical Engineering, RWTH Aachen University, Wüllnerstrasse 5a, 52062 Aachen, Germany

   Physics of Fluids Group, J. M. Burgers Center for Fluid Dynamics and Max Planck Center Twente, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands

   Institute of Aerodynamics and Chair of Fluid Mechanics, Faculty of Mechanical Engineering, RWTH Aachen University, Wüllnerstrasse 5a, 52062, Aachen, Germany