{"id":293803,"date":"2024-10-19T19:58:03","date_gmt":"2024-10-19T19:58:03","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/bs-iso-184812017\/"},"modified":"2024-10-25T17:09:59","modified_gmt":"2024-10-25T17:09:59","slug":"bs-iso-184812017","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/bsi\/bs-iso-184812017\/","title":{"rendered":"BS ISO 18481:2017"},"content":{"rendered":"

This document specifies a method for the estimation of the sub-critical flow of clear water in a smooth, essentially horizontal channel (or a gently sloping channel), abruptly discontinued at bottom by a hydraulic structure, with a vertical drop and discharging freely. Such an overfall forms a control section and offers a means for the estimation of flow using the end depth measurement method. A wide variety of channel cross-sections with overfall have been studied, but only those which have received general acceptance after adequate research and testing, and therefore do not require in situ calibration, are considered. This document covers channels with the following types of cross-sections:<\/p>\n

    \n
  1. \n

    rectangular with confined and unconfined nappe;<\/p>\n<\/li>\n

  2. \n

    trapezoidal;<\/p>\n<\/li>\n

  3. \n

    triangular;<\/p>\n<\/li>\n

  4. \n

    circular;<\/p>\n<\/li>\n

  5. \n

    parabolic.<\/p>\n<\/li>\n<\/ol>\n

    The flow at the brink is curvilinear; therefore, the measured depth at the drop is not equal to the critical depth as computed by the principle based on assumption of parallel flow. However, the end depth and the critical depth (as in the case of the assumption of parallel flow) have unique relation, which is used to estimate the flow through these structures.<\/p>\n

    PDF Catalog<\/h4>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
    PDF Pages<\/th>\nPDF Title<\/th>\n<\/tr>\n
    2<\/td>\nundefined <\/td>\n<\/tr>\n
    7<\/td>\nForeword <\/td>\n<\/tr>\n
    8<\/td>\n1 Scope
    2 Normative references
    3 Terms and definitions <\/td>\n<\/tr>\n
    9<\/td>\n4 Symbols and abbreviated terms
    5 Principle
    6 Installation
    6.1 General
    6.2 Selection of site <\/td>\n<\/tr>\n
    10<\/td>\n7 Measurement of end depth
    7.1 General
    7.2 Head measuring devices
    7.3 Gauge datum
    8 Maintenance
    8.1 General <\/td>\n<\/tr>\n
    11<\/td>\n8.2 Types <\/td>\n<\/tr>\n
    12<\/td>\n8.3 Specifications for the drop structure <\/td>\n<\/tr>\n
    13<\/td>\n8.4 Specifications for installation
    8.5 Determination of gauge zero
    8.6 Discharge relationship
    8.7 Coefficient of discharge
    8.7.1 Confined nappe
    8.7.2 Unconfined nappe
    8.8 Practical limitations <\/td>\n<\/tr>\n
    14<\/td>\n8.9 Uncertainty of measurement
    9 Triangular channel drop structure
    9.1 Specifications for the drop structure
    9.2 Specifications for installation
    9.3 Specifications for head measurement
    9.3.1 General
    9.3.2 Determination of channel angle <\/td>\n<\/tr>\n
    15<\/td>\n9.3.3 Determination of gauge zero
    9.4 Discharge formula \u2014 Unconfined
    9.5 Practical limitations
    9.6 Uncertainty of measurement <\/td>\n<\/tr>\n
    16<\/td>\n10 Trapezoidal channel drop structure
    10.1 Specifications for the drop structure
    10.2 Specifications for head measurement
    10.2.1 General
    10.2.2 Determination of gauge zero
    10.3 Discharge formula \u2014 Unconfined <\/td>\n<\/tr>\n
    17<\/td>\n10.4 Practical limitations
    10.5 Uncertainty of measurement <\/td>\n<\/tr>\n
    18<\/td>\n11 Circular channel drop structure
    11.1 Specifications for the drop structure
    11.2 Specifications for head measurement
    11.2.1 General
    11.2.2 Determination of gauge zero
    11.3 Discharge formula \u2014 Unconfined <\/td>\n<\/tr>\n
    20<\/td>\n11.4 Practical limitations
    11.5 Uncertainty of measurement <\/td>\n<\/tr>\n
    21<\/td>\n12 Parabolic channel drop structure
    12.1 Specifications for the drop structure
    12.2 Specifications for head measurement
    12.2.1 General
    12.2.2 Geometry
    12.2.3 Determination of gauge zero <\/td>\n<\/tr>\n
    22<\/td>\n12.3 Discharge formula \u2014 Unconfined
    12.4 Practical limitations
    13 Uncertainties of flow measurement
    13.1 General
    13.2 Sources of error <\/td>\n<\/tr>\n
    23<\/td>\n13.3 Kinds of error
    13.4 Uncertainties in coefficient values <\/td>\n<\/tr>\n
    24<\/td>\n13.5 Uncertainties in measurements made by the user
    13.6 Combination of uncertainties to give total uncertainty on discharge
    13.7 Example <\/td>\n<\/tr>\n
    27<\/td>\nBibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

    Hydrometry. Liquid flow measurement using end depth method in channels with a free overfall<\/b><\/p>\n\n\n\n\n
    Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
    BSI<\/b><\/a><\/td>\n2017<\/td>\n28<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":293809,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[265,2641],"product_tag":[],"class_list":{"0":"post-293803","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-17-120-20","7":"product_cat-bsi","9":"first","10":"instock","11":"sold-individually","12":"shipping-taxable","13":"purchasable","14":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/293803","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/293809"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=293803"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=293803"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=293803"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}