{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 11: SPILLWAYS" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.1: EX11_1.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "\n", "\n", "//example 11.1\n", "//calculate compute the dynamic force on curved section\n", "clc;funcprot(0);\n", "//given\n", "h=1.2; //head of water\n", "Cd=2.2; //coefficient of discharge\n", "rho=1; //density of water\n", "gamma_w=9.81; //unit weigth of water\n", "\n", "q=Cd*h^1.5;\n", "\n", "//applying bernaulli's equation at u/s water surface at section A and B\n", "//solving it by error and trial method we get\n", "v1=13.7;v2=14.7;\n", "d1=0.212;d2=0.197;\n", "\n", "F1=gamma_w*d1^2*cosd(60)/2;\n", "F2=gamma_w*d2^2/2;\n", "W=gamma_w*60*2*%pi*3*((d1+d2)/2)/360;\n", "Fx=rho*q*(v2-v1*cosd(60))-F1/2+F2;\n", "Fy=rho*q*(v1*sind(60))+F1*sind(60)+W;\n", "F=(Fx^2+Fy^2)^0.5;\n", "F=round(F*100)/100;\n", "mprintf('Resultant force=%f kN/m.',F);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.2: EX11_2.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "\n", "\n", "//example 11.2\n", "//calculate discharge over oggy weir\n", "clc;funcprot(0);\n", "//given\n", "C=2.4; //coefficient of discharge\n", "H=2; //head\n", "L=100; //length of spillway\n", "wc=8; //heigth of weir crest above bottom\n", "g=9.81; //acceleration due to gravity\n", "h=H+wc;\n", "Q1=C*L*H^(1.5); //neglecting approach velocity and end contractions\n", "va=Q1/(h*L);\n", "ha=va^2/(2*g);\n", "Ha=ha+H;\n", "Q=C*L*Ha^1.5;\n", "Q=round(Q*10)/10;\n", "mprintf('discharge over oggy weir=%f cumecs.',Q);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.3: EX11_3.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "\n", "\n", "//example 11.3\n", "//calculate\n", "//capacity of siphon\n", "//head required in oggy spillway\n", "//length of oggy weir required\n", "clc;funcprot(0);\n", "//given\n", "t=6; //tail water elevation\n", "h=1; //heigth of siphon spillway\n", "w=4; //width of siphon spillway\n", "hw=1.5; //head water elevation\n", "C=0.6; //coefficient of discharge\n", "Co=2.25; //coefficient of discharge of oggy spillway\n", "lo=4; //length of oggy spillway\n", "hc=1.5; //head on weir crest\n", "g=9.81; //acceleration due to gravity\n", "\n", "//part (a)\n", "Q=C*h*w*(2*g*(t+hw))^0.5;\n", "Q=round(Q*10)/10;\n", "mprintf('capacity of siphon=%f cumecs.',Q);\n", "\n", "//part (b)\n", "h1=(Q/(Co*lo))^(2/3);\n", "h1=round(h1*100)/100;\n", "mprintf('\nhead required in oggy spillway=%f m',h1);\n", "\n", "//part (c)\n", "L=Q/(Co*(hc)^1.5);\n", "L=round(L*100)/100;\n", "mprintf('\nlength of oggy weir required=%f m.',L);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.4: EX11_4.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "\n", "\n", "//example 11.4\n", "//calculate number of siphons units required\n", "clc;funcprot(0);\n", "//given\n", "rl=435; //full reservior level\n", "cl=429.6; //level of centre of siphon\n", "hfl=435.85; //high flood level\n", "hfd=600; //high flood discharge\n", "w=4; //width of throat\n", "h=2; //heigth of throat\n", "C=0.65; //coefficient of discharge\n", "g=9.81; //acceleration due to gravity\n", "\n", "H=hfl-cl;\n", "Q=C*w*h*(2*g*H)^0.5;\n", "n=hfd/Q;\n", "n=round(n*100)/100;\n", "mprintf(' number of siphons units required=%f.\nhence provide 11 siphons units.',n);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.5: EX11_5.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "\n", "\n", "//example 11.5\n", "//design oggy spillway for concrete gravity dam\n", "clc;funcprot(0);\n", "//given\n", "rbl=250; //avarage river bed level\n", "rlc=350; //R.L of spillway crest\n", "s=0.75; //slope on downstream side\n", "Q=6500; //discharge\n", "L=5*9; //length of spillway\n", "Cd=2.2; //coefficient of discharge\n", "t=2; //thickness of each pier\n", "\n", "//step 1. computation of design head\n", "H=(Q/(Cd*L))^(2/3);\n", "P=rlc-rbl;\n", "\n", "//P/H=6.15,which is<1.33;it is a high overflow spillway\n", "\n", "//H+P/H=7.15>1.7; hence discharge coefficient is not affected by downstream apron interface\n", "\n", "Kp=0.01;Ka=0.1;N=4;\n", "He=17.5; //assumed\n", "Le=L-2*(N*Kp+Ka)*He;\n", "He1=(Q/(Cd*Le))^(2/3);\n", "He1=round(He1*100)/100;\n", "//He1 is almost equal to He\n", "mprintf('crest profile will be designed for Hd=%f m.',He1);\n", "\n", "//step 2. determination of d/s profile\n", "\n", "//equating the slope of d/s side and derivative of profile equation suggested by WES\n", "x=27.03;\n", "y=0.04372*x^1.85;\n", "mprintf('\n\ndownstream profile:');\n", "x=[1:1:26]\n", "for i=1:26\n", " y(i)=0.04372*x(i)^1.85;\n", " y(i)=round(y(i)*1000)/1000;\n", "end\n", "mprintf('\nx y');\n", "for i=1:26\n", " mprintf('\n%i %f',x(i),y(i));\n", "end\n", "mprintf('\n27.03 19.48');\n", "\n", "\n", "//step 3. determination of u/s profile\n", "// cosidering equation for vertical u/s face and Hd=17.58\n", "\n", "mprintf('\n\nupstream profile:');\n", "x=[-0.5 -0.1 -1.5 -2.0 -3.0 -4.0 -4.75];\n", "for i=1:7\n", " y(i)=0.0633*(x(i)+4.7466)^1.85+2.2151-1.2643*(x(i)+4.7466)^0.625;\n", " y(i)=round(y(i)*1000)/1000;\n", "end\n", "mprintf('\nx y');\n", "for i=1:7\n", " mprintf('\n%f %f',x(i),y(i));\n", "end\n", "\n", "//step 4.design of d/s bucket\n", "\n", "R=P/4;\n", "mprintf('\n\nradius of bucket=%i m.',R);\n", "mprintf('\nbucket will subtend angle of 60 degree at the centre.');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.6: EX11_6.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "\n", "\n", "//example 11.6\n", "//design length and depth of stilling basin\n", "clc;funcprot(0);\n", "//given\n", "q=1; //discharge of spillway\n", "Cd=0.7; //coefficient of discharge\n", "h1=10; //heigth of crest above downstream silting basin\n", "g=9.81; //acceleration due to gravity\n", "Cv=0.9; //coefficient of velocity\n", "\n", "h=(3*q/(2*Cd*(2*g)^0.5))^(2/3);\n", "H=h1+h/2;\n", "vt=(2*g*H)^0.5;\n", "v1=Cv*vt;\n", "y1=q/v1;\n", "F1=v1/(g*y1)^0.5;\n", "//F>1, flow is super-critical\n", "y2=1;\n", "v2=q/y2;\n", "F2=v2/(g*y2)^0.5; //<1\n", "y2=(y1/2)*((1+8*F1^2)^0.5-1);\n", "de=y2-1;\n", "le=5*(y2-y1);\n", "de=round(de*1000)/1000;\n", "le=round(le*10)/10;\n", "mprintf('stilling basin should be depressed by %f m.',de);\n", "mprintf('\nlength of stilling basin=%f m.',le);\n", "\n", "" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.7: EX11_7.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "\n", "\n", "//example 11.7\n", "//calculate leading dimension of hydraulic jump stilling basin\n", "clc;funcprot(0);\n", "//given\n", "q=7.83; //discharge through spillway\n", "w=12.5; //width of fall\n", "d=2; //depth of water in downstream\n", "g=9.8;\n", "\n", "y1=0.5;\n", "v1=q/y1;\n", "F1=v1/(g*y1)^0.5;\n", "\n", "//F>1,flow is super-critical\n", "v2=q/d;\n", "F2=v2/(g*d)^0.5;\n", "y2=(y1/2)*((1+8*F1^2)^0.5-1);\n", "de=y2-d;\n", "le=5*(y2-y1);\n", "de=round(de*100)/100;\n", "le=round(le*10)/10;\n", "mprintf('stilling basin should be depressed by %f m.',de);\n", "mprintf('\nlength of stilling basin=%f m.',le); " ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.8: EX11_8.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "\n", "\n", "//example 11.8\n", "//calculate force to be exerted to lift the gate\n", "clc;funcprot(0);\n", "//given\n", "Ag=5*2.5; //area of gate\n", "miu=0.25; //coefficient of friction\n", "w=0.5; //weigth of gate\n", "h=2; //head of water over crest\n", "g=9.81; //acceleration due to gravity\n", "gamma_w=1000; //unit weigth of water\n", "\n", "m=w*g*1000;\n", "F=gamma_w*Ag*h*h*g/10;\n", "ff=miu*F;\n", "tf=(m+ff)/1000;\n", "mprintf('force to be exerted to lift the gate=%f kN.',tf);\n", "" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 11.9: EX11_9.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "\n", "\n", "//example 11.9\n", "//calculate depth of flow at both end of jumps\n", "clc;funcprot(0);\n", "//given\n", "q=19; //dischrge through spillway\n", "E=1; //energy loss\n", "\n", "//from energy loss equation;E=(y2-y1)^3/4y2y1; and solving it we get\n", "//x=0.5*(-1+(1+294.39*(x-1)^9/64*x^3))\n", "//by trial and error method x=2.806\n", "x=2.806;\n", "y1=4*x/(x-1)^3;\n", "y2=x*y1;\n", "y1=round(y1*1000)/1000;\n", "y2=round(y2*1000)/1000;\n", "mprintf('depth of flow at both end of jumps=%f m and %f m. respectively.',y1,y2);\n", "" ] } ], "metadata": { "kernelspec": { "display_name": "Scilab", "language": "scilab", "name": "scilab" }, "language_info": { "file_extension": ".sce", "help_links": [ { "text": "MetaKernel Magics", "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" } ], "mimetype": "text/x-octave", "name": "scilab", "version": "0.7.1" } }, "nbformat": 4, "nbformat_minor": 0 }