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Fluid Flow Through Restrictions

Fluid Flow Through Restrictions 238 AIRCRAFT ENGINEERIN G August, 1943 Correspondence DEA R SIR, b e familiar with it in order to understand the DEA R SIR, I have read with interest the article "Fluid treatmen t which follows. I n reply to the letter of the 6th inst. from Flow through Restrictions "b y L. S. Green­ Yours faithfully, your correspondent A. J. Till, I confirm that land, published in the June issue of your L. S. GREENLAND. th e units for K should be stated as ft-lb/slug/ journal, but feel obliged to comment on two Fairhill, Warwick Road, deg.C. in the Notation column and not ft-lb/lb. things. as shown. Although a careful check was made, Coventry. Firstly, the units in equation (1) are not con­ such errors are sometimes likely to be over­ 14th July, 1943. sistent. K should be expressed in ft. lb. per looked and in this connection it would be as DEA R SIR, slug per deg. C., instead of in ft. lb. per lb. as well to point out that the index to P /P in I thank you for your letter of July 16th, en­ 2 1 given under the heading "Notation." The equation (10) should read (γ-1)/γ and not closing a reply from L. S. Greenland with refer­ fundamental units of each term in equation ence to his article on "Fluid Flow through (γ- )/γ. (1) would then be (length)/(time). Restrictions." Wit h regard to his second point, I agree that Secondly, equation (1) has been proved from I wrote about the question of units because th e proof of Bernouilli's equation given on a thermodynamic point of view, and it, is fol­ the y are of fundamental importance. The mis­ page 10 of Ower's "Measurement of Air Flow " lowed immediately by an alternative form in tak e in equation (10) was also noted, bu t it was is simple t o follow bu t unfortunately it is funda­ equation (la). For a person without prior quite obviously a misprint which would be mentally unsound in so far as it assumes a con­ knowledge of the subject, the relationship be­ appreciated by anybody studying the article. stan t density throughout the element under tween these two equations would not be ap­ I am unable to agree with the autho r tha t the consideration. parent , and as it is th e latter one which is used proof of Bernouilli's theorem given in Ower's Th e proof of equation (1) in th e article is not in th e subsequent analysis, it would have been "Measuremen t of Air Flow " is unsound, for it difficult to follow although a knowledge of bette r if the author had proved it from first only neglects second order differentials. The thermodynamics is assumed, and equation (la) principles. Such a proof is given in "Measure­ autho r does a similar thing in his own analysis. which is used in the subsequent analysis is ment of Air Flow" by E. Ower, one of the A proof, similar to tha t by Ower, is also given derived directly from (1) since references quoted in th e article. in "Aerodynamics" by N. A. V. Piercy. (English Universities Press.) I should be interested to learn the author's reply to these points. I have no objection to the publication of this correspondence. Yours faithfully, A. J . TILL. Yours faithfully, Th e proof of Bernouilli's equation was in­ The Municipal College, The Municipal College, A. J . TILL. cluded for those sufficiently interested in the Portsmouth. Portsmouth. subject, but it is not essential for the reader to 6th July, 1943. 19th July, 1943. Professional Publications Under this heading are given each month the principal articles of aeronautical interest appearing in the current issues of the Journals of the leading Professional Societies and Institutions Th e Journa l of the Institution of Engineering Journa l of th e Aeronautical Sciences should be used with the fast undefended Inspection Mosquito, bu t it should be remembered tha t the Vol. 10, No. 4, April, 1943 Vol. 8, No. 1, Spring, 1943. Ventura has a total of 3,700 h.p., so that its "General Instability of Monocoque Cylinders." N. J. Hoff. "Th e Mechanical Testing of Materials with Special Reference to " A Tabular Method of Propeller Blade Stress Analysis." J. maximu m speed is about 300 m.p.h. the Testing of Welds." V. E . Green. Stuart. The general shape and construction of the "General Equations for the Analysis of Elliptical Wings. " A Brief Summary of Some Simple Methods of Quality Control." Ventur a differs little from the Hudson; there D. O. Dommasch. A. S. Wharton. "Vision, Hearing and Aeronautical Design." L. D. Carson, Reader's Digest. are the same close-set engine nacelles, deep W. R . Miles and S. S. Stevens. "commercial " fuselage, sharply tapered wing " A Method for Rapid Estimation of Helicopter Performance. S.A.E. Journal A. H . Shieh. with Fowler flaps, and distinctive twin rudders. Vol. 51, No. 5, May, 1943. Vol. 10, No. 5, May, 1943. The differences in appearance are the kinked "Ne w Materials for Aircraft Engines." M. Young and H. H. "Bending Strength in the Plastic Range." F. P. Cozzone. trailing edge over the flaps, the under gun Hamnk. " A New Method of Longitudinal Control for Aircraft by Use of "The Influence of Lubricating Oil Viscosity on Cylinder Wear." position near the tail and the more forward an Adjustable Angle of Attack Balance." . R. J . White. H. A. Everett. "Torsional and Aileron Flutter." Z. Krzywoblocki. position of the turret. "Technical Developments in High-Production Sheet Metal Forming." W. Sctroeder and T. H. Hazlett. The engines are the Pratt and Whitney AERONAUTICAL ENGINEERING REVIEW Summaries of Papers read and Discussions a t National Aeronautical R-2800 Double Wasp 18-cylinder radials of Meeting. Vol. 2, No. 5, May, 1943. 1,850 h.p. to 2,000 h.p. The aeroplane was "Thi n Case Hardening with Radio-Frequency Energy." V. W. Transaction s of the Institute of Welding originally designed for lower-powered engines, Sherman. "Second Interim Report of the R.52 Sub-Committee on the Spot so tha t the nacelles are mounted very close to "Plasti c Working of Magnesium Alloy Sheet." C. E . Leinhardt. Welding of Light Alloys." G. H . Field, H. Sutton and H. E . Dixon. th e fuselage and it has been necessary to use "Magnesyn Remote Reading Compass." D. W. Smith. small diameter Hamilton Hydromatic air­ Th e Journa l of the Royal Aeronautical Society screws with very broad blade tips. Vol. XLVII, No. 390, June, 1943. New R.A.F. Types The following details of th e Ventura had been "O n a New Through Free Turbulence." H. Reichardt. Abstracts from the Scientific and Technical Press, etc. released a t the time of writing: XXVIII.—Th e Lockheed Vega Ventura Vol. XLVII, No. 391, July, 1943. I t is armed with eight or ten guns arranged (See page 227) "Post-War Transport Aircraft." (31st Wilbur Wright Memorial as follows: two fixed ·5 in. guns in the nose Lecture.) E. P. Warner. and two further ·302 in. depressible guns in the H E Ventura, which went int o service with Abstracts from the Scientific and Technical Press, etc. nose under the control of the pilot; two or th e R.A.F . towards th e end of last year, is Th e Journal of the Institution of Production a development of th e familiar Hudson. It four ·303 guns in the Boulton Paul top turret; Engineer s was not derived from the Lodestar, as is some­ and two ·303 guns in the under defence posi­ Vol. XXII . No, 5, May, 1943. times stated, but was developed in parallel. tion. The maximum bomb load is 2,500 lb. "Production Control." R. Appleby. The Ventura is built and "fostered" by a Production Engineering Abstracts. PRINCIPAL CHARACTERISTICS subsidiary of the Lockheed Aircraft Corp., the Span ... ... ... ... ... Vol. XXII , No. 6, June, 1943. 65 ft. 6 in. (19·95 m.) Vega Aircraft Corp. Length ... ... ... ... ... 52 ft. 7 in. (16·0 m.) "Machinery Efficiency and Lead-Bearing Steels." Originally the Ventura was intended as a Height ... ... ... ... ... 14 ft. 2 in. (4·3 m.) Abstracts. Wing area ... ... ... ... ... 551 sq. ft. (51·2 sq.m.) replacement for the Hudson in Coastal Com­ TECHNICAL BULLETIN, May, 1943. Gross weight .. . ... ... ... ... 26,000 lb . (11,800 kg.) mand, bu t it has gone int o service with Bomber "Distortion in Heat Treatment in Relation to Carbon and Alloy Tool Steels." T.H.Cole. Command where it has been used very success­ Approximate Performance TECHNICAL BULLETIN, Juno, 1943. Max. Speed ... ... ... ... fully in low-level daylight attacks. I t seems sur­ ... 300 m.p.h. (484 km.p.h.) "Th e Application of Town Gas to Industrial Drying Processes." Cruising speed ... ... ... ... 260 m.p.h. (419 km.p h.) prising that such a bulky turreted aeroplane Max. range ... ... ... ... 1,000 miles (1,610 km.) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

Fluid Flow Through Restrictions

Aircraft Engineering and Aerospace Technology , Volume 15 (8): 1 – Aug 1, 1943

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Emerald Publishing
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Copyright © Emerald Group Publishing Limited
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0002-2667
DOI
10.1108/eb031044
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Abstract

238 AIRCRAFT ENGINEERIN G August, 1943 Correspondence DEA R SIR, b e familiar with it in order to understand the DEA R SIR, I have read with interest the article "Fluid treatmen t which follows. I n reply to the letter of the 6th inst. from Flow through Restrictions "b y L. S. Green­ Yours faithfully, your correspondent A. J. Till, I confirm that land, published in the June issue of your L. S. GREENLAND. th e units for K should be stated as ft-lb/slug/ journal, but feel obliged to comment on two Fairhill, Warwick Road, deg.C. in the Notation column and not ft-lb/lb. things. as shown. Although a careful check was made, Coventry. Firstly, the units in equation (1) are not con­ such errors are sometimes likely to be over­ 14th July, 1943. sistent. K should be expressed in ft. lb. per looked and in this connection it would be as DEA R SIR, slug per deg. C., instead of in ft. lb. per lb. as well to point out that the index to P /P in I thank you for your letter of July 16th, en­ 2 1 given under the heading "Notation." The equation (10) should read (γ-1)/γ and not closing a reply from L. S. Greenland with refer­ fundamental units of each term in equation ence to his article on "Fluid Flow through (γ- )/γ. (1) would then be (length)/(time). Restrictions." Wit h regard to his second point, I agree that Secondly, equation (1) has been proved from I wrote about the question of units because th e proof of Bernouilli's equation given on a thermodynamic point of view, and it, is fol­ the y are of fundamental importance. The mis­ page 10 of Ower's "Measurement of Air Flow " lowed immediately by an alternative form in tak e in equation (10) was also noted, bu t it was is simple t o follow bu t unfortunately it is funda­ equation (la). For a person without prior quite obviously a misprint which would be mentally unsound in so far as it assumes a con­ knowledge of the subject, the relationship be­ appreciated by anybody studying the article. stan t density throughout the element under tween these two equations would not be ap­ I am unable to agree with the autho r tha t the consideration. parent , and as it is th e latter one which is used proof of Bernouilli's theorem given in Ower's Th e proof of equation (1) in th e article is not in th e subsequent analysis, it would have been "Measuremen t of Air Flow " is unsound, for it difficult to follow although a knowledge of bette r if the author had proved it from first only neglects second order differentials. The thermodynamics is assumed, and equation (la) principles. Such a proof is given in "Measure­ autho r does a similar thing in his own analysis. which is used in the subsequent analysis is ment of Air Flow" by E. Ower, one of the A proof, similar to tha t by Ower, is also given derived directly from (1) since references quoted in th e article. in "Aerodynamics" by N. A. V. Piercy. (English Universities Press.) I should be interested to learn the author's reply to these points. I have no objection to the publication of this correspondence. Yours faithfully, A. J . TILL. Yours faithfully, Th e proof of Bernouilli's equation was in­ The Municipal College, The Municipal College, A. J . TILL. cluded for those sufficiently interested in the Portsmouth. Portsmouth. subject, but it is not essential for the reader to 6th July, 1943. 19th July, 1943. Professional Publications Under this heading are given each month the principal articles of aeronautical interest appearing in the current issues of the Journals of the leading Professional Societies and Institutions Th e Journa l of the Institution of Engineering Journa l of th e Aeronautical Sciences should be used with the fast undefended Inspection Mosquito, bu t it should be remembered tha t the Vol. 10, No. 4, April, 1943 Vol. 8, No. 1, Spring, 1943. Ventura has a total of 3,700 h.p., so that its "General Instability of Monocoque Cylinders." N. J. Hoff. "Th e Mechanical Testing of Materials with Special Reference to " A Tabular Method of Propeller Blade Stress Analysis." J. maximu m speed is about 300 m.p.h. the Testing of Welds." V. E . Green. Stuart. The general shape and construction of the "General Equations for the Analysis of Elliptical Wings. " A Brief Summary of Some Simple Methods of Quality Control." Ventur a differs little from the Hudson; there D. O. Dommasch. A. S. Wharton. "Vision, Hearing and Aeronautical Design." L. D. Carson, Reader's Digest. are the same close-set engine nacelles, deep W. R . Miles and S. S. Stevens. "commercial " fuselage, sharply tapered wing " A Method for Rapid Estimation of Helicopter Performance. S.A.E. Journal A. H . Shieh. with Fowler flaps, and distinctive twin rudders. Vol. 51, No. 5, May, 1943. Vol. 10, No. 5, May, 1943. The differences in appearance are the kinked "Ne w Materials for Aircraft Engines." M. Young and H. H. "Bending Strength in the Plastic Range." F. P. Cozzone. trailing edge over the flaps, the under gun Hamnk. " A New Method of Longitudinal Control for Aircraft by Use of "The Influence of Lubricating Oil Viscosity on Cylinder Wear." position near the tail and the more forward an Adjustable Angle of Attack Balance." . R. J . White. H. A. Everett. "Torsional and Aileron Flutter." Z. Krzywoblocki. position of the turret. "Technical Developments in High-Production Sheet Metal Forming." W. Sctroeder and T. H. Hazlett. The engines are the Pratt and Whitney AERONAUTICAL ENGINEERING REVIEW Summaries of Papers read and Discussions a t National Aeronautical R-2800 Double Wasp 18-cylinder radials of Meeting. Vol. 2, No. 5, May, 1943. 1,850 h.p. to 2,000 h.p. The aeroplane was "Thi n Case Hardening with Radio-Frequency Energy." V. W. Transaction s of the Institute of Welding originally designed for lower-powered engines, Sherman. "Second Interim Report of the R.52 Sub-Committee on the Spot so tha t the nacelles are mounted very close to "Plasti c Working of Magnesium Alloy Sheet." C. E . Leinhardt. Welding of Light Alloys." G. H . Field, H. Sutton and H. E . Dixon. th e fuselage and it has been necessary to use "Magnesyn Remote Reading Compass." D. W. Smith. small diameter Hamilton Hydromatic air­ Th e Journa l of the Royal Aeronautical Society screws with very broad blade tips. Vol. XLVII, No. 390, June, 1943. New R.A.F. Types The following details of th e Ventura had been "O n a New Through Free Turbulence." H. Reichardt. Abstracts from the Scientific and Technical Press, etc. released a t the time of writing: XXVIII.—Th e Lockheed Vega Ventura Vol. XLVII, No. 391, July, 1943. I t is armed with eight or ten guns arranged (See page 227) "Post-War Transport Aircraft." (31st Wilbur Wright Memorial as follows: two fixed ·5 in. guns in the nose Lecture.) E. P. Warner. and two further ·302 in. depressible guns in the H E Ventura, which went int o service with Abstracts from the Scientific and Technical Press, etc. nose under the control of the pilot; two or th e R.A.F . towards th e end of last year, is Th e Journal of the Institution of Production a development of th e familiar Hudson. It four ·303 guns in the Boulton Paul top turret; Engineer s was not derived from the Lodestar, as is some­ and two ·303 guns in the under defence posi­ Vol. XXII . No, 5, May, 1943. times stated, but was developed in parallel. tion. The maximum bomb load is 2,500 lb. "Production Control." R. Appleby. The Ventura is built and "fostered" by a Production Engineering Abstracts. PRINCIPAL CHARACTERISTICS subsidiary of the Lockheed Aircraft Corp., the Span ... ... ... ... ... Vol. XXII , No. 6, June, 1943. 65 ft. 6 in. (19·95 m.) Vega Aircraft Corp. Length ... ... ... ... ... 52 ft. 7 in. (16·0 m.) "Machinery Efficiency and Lead-Bearing Steels." Originally the Ventura was intended as a Height ... ... ... ... ... 14 ft. 2 in. (4·3 m.) Abstracts. Wing area ... ... ... ... ... 551 sq. ft. (51·2 sq.m.) replacement for the Hudson in Coastal Com­ TECHNICAL BULLETIN, May, 1943. Gross weight .. . ... ... ... ... 26,000 lb . (11,800 kg.) mand, bu t it has gone int o service with Bomber "Distortion in Heat Treatment in Relation to Carbon and Alloy Tool Steels." T.H.Cole. Command where it has been used very success­ Approximate Performance TECHNICAL BULLETIN, Juno, 1943. Max. Speed ... ... ... ... fully in low-level daylight attacks. I t seems sur­ ... 300 m.p.h. (484 km.p.h.) "Th e Application of Town Gas to Industrial Drying Processes." Cruising speed ... ... ... ... 260 m.p.h. (419 km.p h.) prising that such a bulky turreted aeroplane Max. range ... ... ... ... 1,000 miles (1,610 km.)

Journal

Aircraft Engineering and Aerospace TechnologyEmerald Publishing

Published: Aug 1, 1943

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