The boundary layer equations for plane, incompressible, and steady flow are 

$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Boundary Layer Theory

Aircraft icing: an ongoing threat to aviation safety

Wind turbines in cold climates refer to sites that may experience significant time or frequency of either icing events or low temperatures outside the op- erational limits of standard wind turbines. The potential for producing electric- ity at such, often inhabited, sites is vast. Consequently, the International En- ergy Agency, IEA RDD Task 19-Wind Energy in Cold Climates. The goal of the cooperation is to monitor reliability of standard and adapted technology and establish guide- lines for applying wind power in cold climates. In this report, the state-of-the- art of arctic wind energy is presented: knowledge on climatic conditions and resources, technical solutions in use and operational experience of wind tur- bines in cold climates. This is the updated version of the first State-of-the-art report published in 2003.

/pdf/state-of-the-art-of-wind-energy-in-cold-climates-1k0uabqgn2.pdf

State-of-the-art of wind energy in cold climates

An experimental investigation on the unsteady heat transfer process over an ice accreting airfoil surface

Aerodynamic wind tunnel tests were conducted to study the effects of various ice accretions on the aerodynamic performance of a 36-inch chord, two-dimensional business jet airfoil. Eight different ice shape configurations were tested. Four were castings made from molds of ice shapes accreted in an icing wind tunnel. Two were made using computationally smoothed tracings of two of the ice shapes accreted in the icing tunnel. These smoothed profiles were then extended in the spanwise direction to form a two-dimensional ice shape. The final two configurations were formed by applying grit to the smoothed ice shapes. The ice shapes resulted in as much as 48% reduction in maximum lift coefficient from that of the clean airfoil. Large increases in drag and changes in pitching moment were also observed. The castings and their corresponding smoothed counterparts yielded similar results. Little change in performance was observed with the addition of grit to the smoothed ice shapes. Changes in the Reynolds number (from 3 x 10(exp 6) to 10.5 x 10(exp 6) and Mach number (from 0.12 to 0.28) did not significantly affect the iced-airfoil performance coefficients.

/pdf/a-wind-tunnel-study-of-icing-effects-on-a-business-jet-4272p21koj.pdf

A Wind Tunnel Study of Icing Effects on a Business Jet Airfoil

A research project is underway at NASA Glenn to produce a computer code which can accurately predict ice growth under a wide range of meteorological conditions for any aircraft surface. This report will present a description of the code inputs and outputs from version 2.2.2 of this code, which is called LEWICE. This version differs from release 2.0 due to the addition of advanced thermal analysis capabilities for de-icing and anti-icing applications using electrothermal heaters or bleed air applications. An extensive effort was also undertaken to compare the results against the database of electrothermal results which have been generated in the NASA Glenn Icing Research Tunnel (IRT) as was performed for the validation effort for version 2.0. This report will primarily describe the features of the software related to the use of the program. Appendix A of this report has been included to list some of the inner workings of the software or the physical models used. This information is also available in the form of several unpublished documents internal to NASA. This report is intended as a replacement for all previous user manuals of LEWICE. In addition to describing the changes and improvements made for this version, information from previous manuals may be duplicated so that the user will not need to consult previous manuals to use this code.

/pdf/user-manual-for-the-nasa-glenn-ice-accretion-code-lewice-511303hv7k.pdf

William B. Wright

Papers

User Manual for the NASA Glenn Ice Accretion Code LEWICE: Version 2.0