X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 10 Apr 2007 22:58:46 -0400 Message-ID: X-Original-Return-Path: Received: from imo-m26.mx.aol.com ([64.12.137.7] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTP id 1977664 for lml@lancaironline.net; Tue, 10 Apr 2007 11:22:50 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.7; envelope-from=REHBINC@aol.com Received: from REHBINC@aol.com by imo-m26.mx.aol.com (mail_out_v38_r8.1.) id q.c1d.149ad895 (29679) for ; Tue, 10 Apr 2007 11:14:56 -0400 (EDT) From: REHBINC@aol.com X-Original-Message-ID: X-Original-Date: Tue, 10 Apr 2007 11:14:56 EDT Subject: Re: [LML] FW: [LML] Heat drag and speed records - The Macchi-Cactold MC-72 X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1176218096" X-Mailer: 9.0 for Windows sub 5126 X-Spam-Flag: NO -------------------------------1176218096 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Just to elaborate a little on Fred's post, A turbulent boundary layer of a given thickness has much higher heat transfer than a laminar boundary layer. If you look at the heat transfer of a turbine airfoil section, the two worst points are at the leading edge and at the transition to turbulent boundary layer. My recolection is that the transition point actually has the higher heat load, even though the boundary layer is substantially thicker there. Also, in radiators it is common to louver the fins in order to increase turbulence, and therefore heat transfer. The effect is much the same as adding turbulators ahead of the ailerons. Energy from the free stream is circulated down into the boundary layer where it can be used for heat transfer of control force. Rob ************************************** See what's free at http://www.aol.com. -------------------------------1176218096 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Just to elaborate a little on Fred's post, A turbulent boundary layer o= f a given thickness has much higher heat transfer than a laminar boundary la= yer. If you look at the heat transfer of a turbine airfoil section, the two=20= worst points are at the leading edge and at the transition to turbulent boun= dary layer. My recolection is that the transition point actually has the hig= her heat load, even though the boundary layer is substantially thicker there= .

Also, in radiators it is common to louver the fins in order to increase= turbulence, and therefore heat transfer. The effect is much the same as add= ing turbulators ahead of the ailerons. Energy from the free stream is circul= ated down into the boundary layer where it can be used for heat transfer of=20= control force.

Rob

See what's free at AOL.com. -------------------------------1176218096--