Design Studies on NLF and HLFC Applications at DLR

Kurzfassung

The Vision 2020 of the Advisory Council for Aeronautical Research in Europe (ACARE) demands an environmentally friendly and sustainable growth of air transport. The goal is to substantially reduce emissions of carbon dioxides (by 50%) and nitrogen oxides (by 80%). But also lowering costs (by 30%) plays an important role. It is obvious that such ambitious goals cannot be matched with small improvements on existing aircraft designs but are only possible with a leap in technology. In the field of aero-dynamics boundary laminarization offers such a leap because of its high potential in drag and, hence, fuel burn reduction. At the German Aerospace Center DLR research on laminar flow for transport aircraft flying in the transonic regime started by the mid eighties of the last century. Basic as well as applied re-search was performed. The intention of the pre-sent paper is to give an overview on design studies for transonic wings with natural laminar flow (NLF) and hybrid laminar flow control (HLFC) performed at DLR. over a period of 25 years. Design principals and the tools used are explained.