New positional control valve added

ReleaseNotes2_3.md

@@ -24,6 +24,7 @@ This document describes the changes and updates that have been made in version 2
    - dropping the check for identical status report content since it prevents accepting code changes that produce more accurate solutions in fewer iterations.
  - A possible loss of network connectivity when evaluating a Pressure Sustaining Valve was prevented.
  - Having the implied loss coefficient for an active Flow Control Valve be less than its fully opened value was prevented.
+ - A new type of valve, a Positional Control Valve (PCV), was added that uses a valve characteristic curve to relate its loss coefficient to its fraction open setting. 
  
  
 

doc/input-file.dox

@@ -92,9 +92,10 @@ __Remarks:__
    - Head v. Flow for pumps
    - Efficiency v. Flow for pumps
    - Volume v. Depth for tanks
+   - Fraction of fully open flow v. fraction open for Positional Control Valves
    - Head Loss v. Flow for General Purpose Valves
 2. The points of a curve must be entered in order of increasing X-values (lower to higher).
-3. If the input file will be used with the Windows version of EPANET, then adding a comment which contains the curve type and description, separated by a colon, directly above the first entry for a curve will ensure that these items appear correctly in EPANET's Curve Editor. Curve types include <B>PUMP, EFFICIENCY, VOLUME</B>, and <B>HEADLOSS</B>. See the examples below.
+3. If the input file will be used with the Windows version of EPANET, then adding a comment which contains the curve type and description, separated by a colon, directly above the first entry for a curve will ensure that these items appear correctly in EPANET's Curve Editor. Curve types include <B>PUMP, EFFICIENCY, VOLUME, VALVE</B>, and <B>HEADLOSS</B>. See the examples below.
 
 __Example:__
 ```
@@ -1028,7 +1029,8 @@ One line for each valve containing:
 - Diameter, inches (mm)
 - Valve type
 - Valve setting
-- Minor loss coefficient
+- Minor loss coefficient when fully open
+- ID of valve characteristic curve (PCVs only)
 
 __Remarks:__
 1. Valve types and settings include:
@@ -1038,9 +1040,13 @@ __Remarks:__
 |<B>PSV</B> (pressure sustaining valve) | Pressure, psi (m) |
 |<B>PBV</B> (pressure breaker valve) | Pressure, psi (m) |
 |<B>FCV</B> (flow control valve) | Flow (flow units) |
-|<B>TCV</B> (throttle control valve) | Loss Coefficient |
+|<B>TCV</B> (throttle control valve) | Partially open loss coefficient |
+|<B>PCV</B> (positional control valve) | Fraction open |
 |<B>GPV</B> (general purpose valve) | ID of head loss curve |
 2. Shutoff valves and check valves are considered to be part of a pipe, not a separate control valve component (see @ref PipesPage).
+3. The loss coefficient setting for a TCV should not be less than its fully open loss coefficient.
+4. The characteristic curve for a PCV relates the valve's fraction of fully open flow to the fraction open.
+5. The head loss curve for a GPV relates head loss across the valve to the flow rate through it.
 */
 
 /**

include/epanet2_enums.h

@@ -9,7 +9,7 @@
  Authors:      see AUTHORS
  Copyright:    see AUTHORS
  License:      see LICENSE
- Last Updated: 02/01/2020
+ Last Updated: 08/13/2022
  ******************************************************************************
 */
 
@@ -97,7 +97,8 @@ typedef enum {
   EN_PUMP_ECOST   = 21, //!< Pump average energy price
   EN_PUMP_EPAT    = 22, //!< Pump energy price time pattern index
   EN_LINK_INCONTROL = 23,  //!< Is present in any simple or rule-based control (= 1) or not (= 0)
-  EN_GPV_CURVE    = 24  //!< GPV head loss v. flow curve index
+  EN_GPV_CURVE    = 24, //!< GPV head loss v. flow curve index
+  EN_PCV_CURVE    = 25  //!< PCV loss coeff. curve index
 } EN_LinkProperty;
 
 /// Time parameters
@@ -191,7 +192,8 @@ typedef enum {
   EN_PBV          = 5,  //!< Pressure breaker valve
   EN_FCV          = 6,  //!< Flow control valve
   EN_TCV          = 7,  //!< Throttle control valve
-  EN_GPV          = 8   //!< General purpose valve
+  EN_GPV          = 8,  //!< General purpose valve
+  EN_PCV          = 9   //!< Positional control valve
 } EN_LinkType;
 
 /// Link status
@@ -397,7 +399,8 @@ typedef enum {
   EN_PUMP_CURVE    = 1,   //!< Pump head v. flow curve
   EN_EFFIC_CURVE   = 2,   //!< Pump efficiency v. flow curve
   EN_HLOSS_CURVE   = 3,   //!< Valve head loss v. flow curve
-  EN_GENERIC_CURVE = 4    //!< Generic curve
+  EN_GENERIC_CURVE = 4,   //!< Generic curve
+  EN_VALVE_CURVE   = 5    //!< Valve loss coeff. v. frac. open
 } EN_CurveType;
 
 /// Deletion action codes

src/enumstxt.h

@@ -7,7 +7,7 @@
  Authors:      see AUTHORS
  Copyright:    see AUTHORS
  License:      see LICENSE
- Last Updated: 06/20/2019
+ Last Updated: 08/13/2022
  ******************************************************************************
 */
 
@@ -27,7 +27,8 @@ char *LinkTxt[]         = {w_CV,
                            w_PBV,
                            w_FCV,
                            w_TCV,
-                           w_GPV};
+                           w_GPV,
+                           w_PCV};
 
 char *StatTxt[]         = {t_XHEAD,
                            t_TEMPCLOSED,

src/epanet.c

@@ -7,7 +7,7 @@
  Authors:      see AUTHORS
  Copyright:    see AUTHORS
  License:      see LICENSE
- Last Updated: 11/08/2020
+ Last Updated: 08/13/2022
  ******************************************************************************
 */
 
@@ -3149,7 +3149,7 @@ int DLLEXPORT EN_addlink(EN_Project p, char *id, int linkType,
     if (EN_getlinkindex(p, id, &i) == 0) return 215;
 
     // Check for valid link type
-    if (linkType < CVPIPE || linkType > GPV) return 251;
+    if (linkType < CVPIPE || linkType > PCV) return 251;
 
     // Lookup the link's from and to nodes
     n1 = hashtable_find(net->NodeHashTable, fromNode);
@@ -3209,6 +3209,7 @@ int DLLEXPORT EN_addlink(EN_Project p, char *id, int linkType,
         size = (net->Nvalves + 1) * sizeof(Svalve);
         net->Valve = (Svalve *)realloc(net->Valve, size);
         net->Valve[net->Nvalves].Link = n;
+        net->Valve[net->Nvalves].Curve = 0;
     }
 
     link->Type = linkType;
@@ -3468,7 +3469,7 @@ int DLLEXPORT EN_setlinktype(EN_Project p, int *index, int linkType, int actionC
     if (p->hydraul.OpenHflag || p->quality.OpenQflag) return 262;
 
     // Check for valid input parameters
-    if (linkType < 0 || linkType > GPV || actionCode < EN_UNCONDITIONAL ||
+    if (linkType < 0 || linkType > PCV || actionCode < EN_UNCONDITIONAL ||
         actionCode > EN_CONDITIONAL)
     {
         return 251;
@@ -3794,6 +3795,13 @@ int DLLEXPORT EN_getlinkvalue(EN_Project p, int index, int property, double *val
         }
         break;
         
+    case EN_PCV_CURVE:
+        if (Link[index].Type == PCV)
+        {
+            v = net->Valve[findvalve(&p->network, index)].Curve;
+        }
+        break;
+            
     case EN_GPV_CURVE:
         if (Link[index].Type == GPV)
         {
@@ -3916,6 +3924,7 @@ int DLLEXPORT EN_setlinkvalue(EN_Project p, int index, int property, double valu
                 value /= Ucf[FLOW];
                 break;
             case TCV:
+            case PCV:
                 break;
             case GPV:
                 return 207; // Cannot modify setting for GPV
@@ -4012,6 +4021,15 @@ int DLLEXPORT EN_setlinkvalue(EN_Project p, int index, int property, double valu
         }
         break;
         
+    case EN_PCV_CURVE:
+        if (Link[index].Type == PCV)
+        {
+            curveIndex = ROUND(value);
+            if (curveIndex < 0 || curveIndex > net->Ncurves) return 206;
+            net->Valve[findvalve(&p->network, index)].Curve = curveIndex;
+        }
+        break;
+        
     case EN_GPV_CURVE:
         if (Link[index].Type == GPV)
         {

src/funcs.h

@@ -7,7 +7,7 @@
  Authors:      see AUTHORS
  Copyright:    see AUTHORS
  License:      see LICENSE
- Last Updated: 02/03/2020
+ Last Updated: 08/13/2022
  ******************************************************************************
 */
 #ifndef FUNCS_H
@@ -166,6 +166,7 @@ void    headlosscoeffs(Project *);
 void    matrixcoeffs(Project *);
 void    emitterheadloss(Project *, int, double *, double *);           
 void    demandheadloss(Project *, int, double, double, double *, double *);
+double  pcvlosscoeff(Project *, int, double);
 
 // ------- QUALITY.C --------------------
 

src/hydcoeffs.c

@@ -7,7 +7,7 @@
  Authors:      see AUTHORS
  Copyright:    see AUTHORS
  License:      see LICENSE
- Last Updated: 03/30/2022
+ Last Updated: 08/13/2022
  ******************************************************************************
 */
 
@@ -36,6 +36,7 @@ const double CBIG   = 1.e8;
 
 // Exported functions
 //void   resistcoeff(Project *, int );
+//double pcvlosscoeff(Project *, int, double);
 //void   headlosscoeffs(Project *);
 //void   matrixcoeffs(Project *);
 //void   emitterheadloss(Project *, int, double *, double *);
@@ -59,6 +60,7 @@ static void    valvecoeff(Project *pr, int k);
 static void    gpvcoeff(Project *pr, int k);
 static void    pbvcoeff(Project *pr, int k);
 static void    tcvcoeff(Project *pr, int k);
+static void    pcvcoeff(Project *pr, int k);
 static void    prvcoeff(Project *pr, int k, int n1, int n2);
 static void    psvcoeff(Project *pr, int k, int n1, int n2);
 static void    fcvcoeff(Project *pr, int k, int n1, int n2);
@@ -108,6 +110,10 @@ void  resistcoeff(Project *pr, int k)
         link->R = CBIG;
         break;
         
+    case PCV:
+        link->R = pcvlosscoeff(pr, k, link->Kc);
+        break;
+
     // ... For all other links (e.g. valves) use a small resistance
     default:
         link->R = CSMALL;
@@ -116,6 +122,86 @@ void  resistcoeff(Project *pr, int k)
 }
 
 
+double pcvlosscoeff(Project* pr, int k, double s)
+/*
+**--------------------------------------------------------------
+**   Input:   k = link index
+**            s = valve fraction open setting
+**   Output:  returns a valve loss coefficient
+**   Purpose: finds a Positional Control Valve's loss
+**            coefficient from its fraction open setting.
+**--------------------------------------------------------------
+*/
+{
+    Network* net = &pr->network;
+    
+    int v = findvalve(net, k);         // valve index
+    int c = net->Valve[v].Curve;       // Kv curve index
+    double d;                          // valve diameter
+    double kmo;                        // fully open loss coeff.
+    double km;                         // partly open loss coeff.
+    double kvr;                        // Kv / Kvo (Kvo = Kv at fully open)
+    double *x, *y;                     // points on kvr v. frac. open curve
+    int k1, k2, npts;
+    Scurve *curve;
+
+    // Valve has no setting so return 0
+    if (s == MISSING) return 0.0;
+    
+    // Valve is completely open so return its Km value
+    d = net->Link[k].Diam;
+    kmo = net->Link[k].Km;
+    if (s >= 1.0) return kmo;
+    
+    // Valve is completely closed so return a large coeff.
+    if (s <= 0.0) return CBIG;
+    
+    // Valve has no assigned curve so assume a linear one
+    if (c == 0) kvr = s;
+
+    else
+    {        
+        // Valve curve data
+        curve = &net->Curve[c];
+        npts = curve->Npts;
+        x = curve->X;            // x = frac. open
+        y = curve->Y;            // y = Kv / Kvo
+    
+        // s lies below first point of curve
+        if (s < x[0])
+            kvr = s / x[0] * y[0];
+    
+        // s lies above last point of curve
+        else if (s > x[npts-1])
+        {
+            k2 = npts - 1;
+            kvr = (s - x[k2]) / (1. -  x[k2]) * (1. - y[k2]) + y[k2];
+        }
+    
+        // Otherwise interpolate over curve segment that brackets s
+        else 
+        {
+            k2 = 0;
+            while (k2 < npts && x[k2] < s) k2++;
+            if (k2 == 0) k2++;
+            else if (k2 == npts)  k2--;
+            k1 = k2 - 1;
+            kvr = (y[k2] - y[k1]) / (x[k2] - x[k1]);
+            kvr = y[k1] + kvr * (s - x[k1]);
+        }
+    }
+
+    // kvr can't be > 1 or <= 0    
+    kvr = MIN(kvr, 1.0);
+    kvr = MAX(kvr, CSMALL);
+    
+    // Convert from Kv ratio to minor loss coeff.
+    km = kmo / (kvr * kvr);
+    km = MIN(km, CBIG);
+    return km;
+}    
+
+
 void headlosscoeffs(Project *pr)
 /*
 **--------------------------------------------------------------
@@ -148,6 +234,9 @@ void headlosscoeffs(Project *pr)
         case TCV:
             tcvcoeff(pr, k);
             break;
+        case PCV:
+            pcvcoeff(pr, k);
+            break;
         case GPV:
             gpvcoeff(pr, k);
             break;
@@ -945,6 +1034,36 @@ void  tcvcoeff(Project *pr, int k)
 }
 
 
+void  pcvcoeff(Project *pr, int k)
+/*
+**--------------------------------------------------------------
+**   Input:   k = link index
+**   Output:  none
+**   Purpose: computes P & Y coeffs. for positional control valve
+**--------------------------------------------------------------
+*/
+{
+    double km;
+    Hydraul *hyd = &pr->hydraul;
+    Slink *link = &pr->network.Link[k];
+
+    // Save original loss coeff. for open valve
+    km = link->Km;
+
+    // If valve not fixed OPEN or CLOSED, compute its loss coeff.
+    if (hyd->LinkSetting[k] != MISSING)
+    {
+        link->Km = link->R;
+    }
+
+    // Then apply usual valve formula
+    valvecoeff(pr, k);
+
+    // Restore original loss coeff.
+    link->Km = km;
+}
+
+
 void  prvcoeff(Project *pr, int k, int n1, int n2)
 /*
 **--------------------------------------------------------------

src/hydraul.c

@@ -7,7 +7,7 @@
  Authors:      see AUTHORS
  Copyright:    see AUTHORS
  License:      see LICENSE
- Last Updated: 03/19/2022
+ Last Updated: 08/13/2022
  ******************************************************************************
 */
 
@@ -450,6 +450,7 @@ void  setlinksetting(Project *pr, int index, double value, StatusType *s,
     else
     {
         if (*k == MISSING && *s <= CLOSED) *s = OPEN;
+        if (t == PCV) link->R = pcvlosscoeff(pr, index, link->Kc);
         *k = value;
     }
 }
@@ -605,6 +606,7 @@ int  controls(Project *pr)
             {
                 hyd->LinkStatus[k] = s2;
                 hyd->LinkSetting[k] = k2;
+                if (link->Type == PCV) link->R = pcvlosscoeff(pr, k, k2);
                 if (pr->report.Statflag) writecontrolaction(pr,k,i);
                 setsum++;
             }

src/inpfile.c

@@ -7,7 +7,7 @@ Description:  saves network data to an EPANET formatted text file
 Authors:      see AUTHORS
 Copyright:    see AUTHORS
 License:      see LICENSE
-Last Updated: 10/29/2019
+Last Updated: 08/13/2022
 ******************************************************************************
 */
 
@@ -312,6 +312,11 @@ int saveinpfile(Project *pr, const char *fname)
         {
             sprintf(s1, "%-31s %12.4f", net->Curve[j].ID, km);
         }
+        // For PCV add loss curve if present
+        else if (link->Type == PCV && (j = net->Valve[i].Curve) > 0)
+        {
+            sprintf(s1, "%12.4f %12.4f %-31s", kc, km, net->Curve[j].ID);
+        }
         else sprintf(s1, "%12.4f %12.4f", kc, km);
         fprintf(f, "\n%s %s", s, s1);
         if (link->Comment) fprintf(f, " ;%s", link->Comment);

src/input3.c

@@ -7,7 +7,7 @@ Description:  parses network data from a line of an EPANET input file
 Authors:      see AUTHORS
 Copyright:    see AUTHORS
 License:      see LICENSE
-Last Updated: 03/20/2022
+Last Updated: 08/13/2022
 ******************************************************************************
 */
 
@@ -471,7 +471,7 @@ int valvedata(Project *pr)
 **  Purpose: processes valve data
 **  Format:
 **     [VALVE]
-**        id  node1  node2  diam  type  setting (lcoeff)
+**        id  node1  node2  diam  type  setting (lcoeff  lcurve)
 **--------------------------------------------------------------
 */
 {
@@ -488,7 +488,8 @@ int valvedata(Project *pr)
            setting,            // Valve setting
            lcoeff = 0.0;       // Minor loss coeff.
     Slink *link;
-    int err = 0;
+    int err = 0,
+        losscurve = 0;          // Loss coeff. curve
 
     // Add new valve to data base
     n = parser->Ntokens;
@@ -521,6 +522,8 @@ int valvedata(Project *pr)
       type = TCV;
     else if (match(parser->Tok[4], w_GPV))
       type = GPV;
+    else if (match(parser->Tok[4], w_PCV))
+      type = PCV;
     else
       return setError(parser, 4, 213);
 
@@ -539,6 +542,16 @@ int valvedata(Project *pr)
     else if (!getfloat(parser->Tok[5], &setting)) return setError(parser, 5, 202);
     if (n >= 7 && !getfloat(parser->Tok[6], &lcoeff)) return setError(parser, 6, 202);
     
+    // Find loss coeff. curve for PCV
+    if (type == PCV && n >= 8)
+    {
+        c = findcurve(net, parser->Tok[7]);
+        if (c == 0) return setError(parser, 7, 206);
+        losscurve = c;
+        net->Curve[c].Type = VALVE_CURVE;
+        if (setting > 1.0) setting = 1.0;
+    }        
+
     // Check for illegal connections
     if (valvecheck(pr, net->Nlinks, type, j1, j2))
     {
@@ -563,6 +576,7 @@ int valvedata(Project *pr)
     link->ResultIndex = 0;
     link->Comment = xstrcpy(&link->Comment, parser->Comment, MAXMSG);
     net->Valve[net->Nvalves].Link = net->Nlinks;
+    net->Valve[net->Nvalves].Curve = losscurve;
     return 0;
 }
 

src/output.c

@@ -7,7 +7,7 @@ Description:  binary file read/write routines
 Authors:      see AUTHORS
 Copyright:    see AUTHORS
 License:      see LICENSE
-Last Updated: 05/13/2019
+Last Updated: 08/13/2022
 ******************************************************************************
 */
 
@@ -567,6 +567,7 @@ int linkoutput(Project *pr, int j, REAL4 *x, double ucf)
               case FCV:
                 x[i] = (REAL4)(setting * pr->Ucf[FLOW]); break;
               case TCV:
+              case PCV:
                 x[i] = (REAL4)setting; break;
               default: x[i] = 0.0f;
             }

src/project.c

@@ -7,7 +7,7 @@
  Authors:      see AUTHORS
  Copyright:    see AUTHORS
  License:      see LICENSE
- Last Updated: 02/03/2020
+ Last Updated: 08/13/2022
  ******************************************************************************
 */
 
@@ -860,7 +860,7 @@ int findtank(Network *network, int index)
 /*----------------------------------------------------------------
 **  Input:   index = node index
 **  Output:  none
-**  Returns: index of tank with given node id, or NOTFOUND if tank not found
+**  Returns: index of tank with given node index, or NOTFOUND if tank not found
 **  Purpose: for use in the deletenode function
 **----------------------------------------------------------------
 */
@@ -877,7 +877,7 @@ int findpump(Network *network, int index)
 /*----------------------------------------------------------------
 **  Input:   index = link ID
 **  Output:  none
-**  Returns: index of pump with given link id, or NOTFOUND if pump not found
+**  Returns: index of pump with given link index, or NOTFOUND if pump not found
 **  Purpose: for use in the deletelink function
 **----------------------------------------------------------------
 */
@@ -894,7 +894,7 @@ int findvalve(Network *network, int index)
 /*----------------------------------------------------------------
 **  Input:   index = link ID
 **  Output:  none
-**  Returns: index of valve with given link id, or NOTFOUND if valve not found
+**  Returns: index of valve with given link index, or NOTFOUND if valve not found
 **  Purpose: for use in the deletelink function
 **----------------------------------------------------------------
 */
@@ -1010,7 +1010,7 @@ void adjustcurves(Network *network, int index)
 **----------------------------------------------------------------
 */
 {
-    int j, k, setting;
+    int j, k, curve;
 
     // Adjust tank volume curves
     for (j = 1; j <= network->Ntanks; j++)
@@ -1025,15 +1025,25 @@ void adjustcurves(Network *network, int index)
         adjustcurve(&network->Pump[j].Ecurve, index);
     }
 
-    // Adjust GPV curves
+    // Adjust PCV & GPV curves
     for (j = 1; j <= network->Nvalves; j++)
     {
         k = network->Valve[j].Link;
+        if (network->Link[k].Type == PCV)
+        {
+            if ((curve = network->Valve[j].Curve) > 0)
+            {
+                adjustcurve(&curve, index);
+                network->Valve[j].Curve = curve;
+                if (curve == 0)
+                    network->Link[k].Kc = 0.0;
+            }
+        }
         if (network->Link[k].Type == GPV)
         {
-            setting = INT(network->Link[k].Kc);
+            curve = INT(network->Link[k].Kc);
-            adjustcurve(&setting, index);
+            adjustcurve(&curve, index);
-            network->Link[k].Kc = setting;
+            network->Link[k].Kc = curve;
         }
     }
 }

src/text.h

@@ -7,7 +7,7 @@
  Authors:      see AUTHORS
  Copyright:    see AUTHORS
  License:      see LICENSE
- Last Updated: 07/15/2019
+ Last Updated: 08/13/2022
  ******************************************************************************
 */
 
@@ -40,6 +40,7 @@
 #define   w_FCV         "FCV"
 #define   w_TCV         "TCV"
 #define   w_GPV         "GPV"
+#define   w_PCV         "PCV"
 
 #define   w_OPEN        "OPEN"
 #define   w_CLOSED      "CLOSED"

src/types.h

@@ -7,7 +7,7 @@
  Authors:      see AUTHORS
  Copyright:    see AUTHORS
  License:      see LICENSE
- Last Updated: 07/11/2020
+ Last Updated: 08/13/2022
  ******************************************************************************
 */
 
@@ -145,7 +145,8 @@ typedef enum {
   PBV,           // pressure breaker valve
   FCV,           // flow control valve
   TCV,           // throttle control valve
-  GPV            // general purpose valve
+  GPV,           // general purpose valve
+  PCV            // positional control valve
 } LinkType;
 
 typedef enum {
@@ -166,7 +167,8 @@ typedef enum {
   PUMP_CURVE,    // pump curve
   EFFIC_CURVE,   // efficiency curve
   HLOSS_CURVE,   // head loss curve
-  GENERIC_CURVE  // generic curve
+  GENERIC_CURVE, // generic curve
+  VALVE_CURVE    // positional valve loss curve
 } CurveType;
 
 typedef enum {
@@ -455,6 +457,7 @@ typedef struct             // Pump Object
 typedef struct             // Valve Object
 {
   int Link;                // link index of valve
+  int Curve;               // positional loss coeff. curve
 } Svalve;
 
 typedef struct             // Control Statement

tests/CMakeLists.txt

@@ -39,6 +39,7 @@ set(toolkit_test_srcs
      test_control.cpp
      test_overflow.cpp
      test_pda.cpp
+     test_valve.cpp
 )
 
 add_executable(test_toolkit ${toolkit_test_srcs})

tests/test_valve.cpp

@@ -0,0 +1,73 @@
+/*
+ ******************************************************************************
+ Project:      OWA EPANET
+ Version:      2.2
+ Module:       test_valve.cpp
+ Description:  Tests EPANET toolkit api functions
+ Authors:      see AUTHORS
+ Copyright:    see AUTHORS
+ License:      see LICENSE
+ Last Updated: 07/28/2022
+ ******************************************************************************
+*/
+
+/*
+   Tests PCV valve with position curve
+*/
+
+#include <boost/test/unit_test.hpp>
+
+#include "test_toolkit.hpp"
+
+BOOST_AUTO_TEST_SUITE (test_valve)
+
+BOOST_FIXTURE_TEST_CASE(test_PCV_valve, FixtureOpenClose)
+
+{
+    int npts = 5;
+    double x[] = { 0.0, 0.25, 0.5, 0.75, 1. };
+    double y[] = {0.0, 0.089, 0.184, 0.406, 1.0};
+    double v;
+    int linkIndex, curveIndex;
+
+    // Make steady state run
+    error = EN_settimeparam(ph, EN_DURATION, 0);
+    BOOST_REQUIRE(error == 0);
+
+    // Convert pipe 22 to a PCV
+    error = EN_getlinkindex(ph, (char*)"22", &linkIndex);
+    BOOST_REQUIRE(error == 0);
+    error = EN_setlinktype(ph, &linkIndex, EN_PCV, EN_UNCONDITIONAL);
+    BOOST_REQUIRE(error == 0);
+    error = EN_setlinkvalue(ph, linkIndex, EN_DIAMETER, 12);
+    BOOST_REQUIRE(error == 0);
+    error = EN_setlinkvalue(ph, linkIndex, EN_MINORLOSS, 0.19);
+
+    // Create the PCV's position-loss curve
+    error = EN_addcurve(ph, (char*)"ValveCurve");
+    BOOST_REQUIRE(error == 0);
+    error = EN_getcurveindex(ph, (char*)"ValveCurve", &curveIndex);
+    BOOST_REQUIRE(error == 0);
+    error = EN_setcurve(ph, curveIndex, x, y, npts);
+    BOOST_REQUIRE(error == 0);
+
+    // Assign curve & initial setting to PCV
+    error = EN_setlinkvalue(ph, linkIndex, EN_PCV_CURVE, curveIndex);
+    BOOST_REQUIRE(error == 0);
+    error = EN_setlinkvalue(ph, linkIndex, EN_INITSETTING, 0.35);
+    BOOST_REQUIRE(error == 0);
+
+    // Solve for hydraulics
+    error = EN_solveH(ph);
+    BOOST_REQUIRE(error == 0);
+
+    // The PCV interpolated relative flow coeff. at 0.35 open is 0.127.
+    // This translates to a minor loss coeff. of 0.19 / 0.127^2 = 11.78.
+    // If the PCV were replaced with a TCV at that setting the resulting
+    // head loss would be 0.0255 ft which should equal the PCV result. 
+    error = EN_getlinkvalue(ph, linkIndex, EN_HEADLOSS, &v);
+    BOOST_REQUIRE(error == 0);
+    BOOST_REQUIRE(abs(v - 0.0255) < 0.001);
+}
+
+BOOST_AUTO_TEST_SUITE_END()