52 citations · 223 across the 16 of their papers we have counts for
15 papers · 1 filter
Modern aerodynamics models do not capture important unsteady forces--the failure of the quasi-steady approximation
Victoria M. Malarczyk, Marcus Hultmark
Aerodynamic unsteadiness is inherent to the operation of many engineering applications, especially those that involve large-scale rotating blades, such as modern wind turbines. Ove…
An analytical model for rotors in confined flow across operating regimes
I. M. L. Upfal, K. J. McClure, K. S. Heck +4
Rotors operating in confined flows, or blockage, are commonly encountered in wind and water tunnels, as well as in shallow or dense deployments of hydrokinetic turbines. Confinemen…
Time-varying wind-turbine wakes at high Reynolds numbers
Nathaniel J. Wei, Adina Y. Fleisher, John W. Kurelek +1
Wind turbines operating in the atmospheric boundary layer are constantly exposed to time-varying flow conditions. These disturbances often occur on similar time scales to wind-turb…
Understanding the effects of rotation on the wake of a wind turbine at high Reynolds number
Alexander Pique, Mark A. Miller, Marcus Hultmark
The wake of a horizontal-axis wind turbine was studied at with the aim of revealing the effects of the tip speed ratio, , on the wake. Tip speed ratios of $4<…
Spanwise wall forcing can reduce turbulent heat transfer more than drag
Amirreza Rouhi, Marcus Hultmark, Alexander J. Smits
Direct numerical simulations are performed of turbulent forced convection in a half channel flow with wall oscillating either as a spanwise plane oscillation or to generate a strea…
Contact-angle hysteresis provides resistance to drainage of liquid-infused surfaces in turbulent flows
Sofia Saoncella, Si Suo, Johan Sundin +5
Lubricated textured surfaces immersed in liquid flows offer tremendous potential for reducing fluid drag, enhancing heat and mass transfer, and preventing fouling. According to cur…
Acceleration is the Key to Drag Reduction in Turbulent Flow
Liuyang Ding, Lena Sabidussi, Brian C. Holloway +2
A turbulent pipe flow experiment was conducted where the surface of the pipe was oscillated azimuthally over a wide range of frequencies, amplitudes and Reynolds number. The drag w…
Kirigami-inspired wind steering for natural ventilation
Lucia Stein-Montalvo, Liuyang Ding, Marcus Hultmark +2
Ensuring adequate ventilation of exterior and interior urban spaces is essential for the safety and comfort of inhabitants. Here, we examine how angled features can steer wind into…
Fast-response hot-wire flow sensors for wind and gust estimation on UAVs
Nathaniel Simon, Alexander Piqué, David Snyder +3
Due to limitations in available sensor technology, unmanned aerial vehicles (UAVs) lack an active sensing capability to measure turbulence, gusts, or other unsteady aerodynamic phe…
Heat transfer increase by convection in liquid-infused surfaces for laminar and turbulent flows
Johan Sundin, Umberto Ciri, Stefano Leonardi +2
Liquid-infused surfaces (LIS) can reduce friction drag in both laminar and turbulent flows. However, the heat transfer properties of such multi-phase surfaces have still not been i…
Reynolds stress scaling in the near-wall region of wall-bounded flows
Alexander J. Smits, Marcus Hultmark, Myoungkyu Lee +2
A new scaling is derived that yields a Reynolds number independent profile for all components of the Reynolds stress in the near-wall region of wall bounded flows, including channe…
Reynolds stress scaling in the near-wall region
Alexander J. Smits, Marcus Hultmark
A new scaling is derived that yields a Reynolds number independent profile for all components of the Reynolds stress in the near-wall region of wall bounded flows. The scaling demo…
Scaling turbulence in the near-wall region
Marcus Hultmark, Alexander J. Smits
A new velocity scale is derived that yields a Reynolds number independent profile for the streamwise turbulent fluctuations in the near-wall region of wall bounded flows for $y^+<2…
Comparison between super-hydrophobic, liquid infused and rough surfaces: a DNS study
I. Arenas, E. Garcia, M. K. Fu +3
Direct Numerical Simulations of two superposed fluids in a channel with a textured surface on the lower wall have been carried out. A parametric study varying the viscosity ratio b…
Measurement of local dissipation scales in turbulent pipe flow
Sean C. C. Bailey, Marcus Hultmark, Joerg Schumacher +2
Local dissipation scales are a manifestation of the intermittent small-scale nature of turbulence. We report the first experimental evaluation of the distribution of local dissipat…